The Aquarena Springs Trip

by Robert Laird

January 29-30, 1994 Aquarena Springs, San Marcos, Tx

There is an update to this story... see the bottom of this page for more information.

Aquarena Springs is located in the gently rolling hills of central Texas. The Edwards Aquifer, a huge underground lake that covers most of central Texas, filters 150 million gallons of water per day through 175 miles of limestone hills and comes up at Spring Lake, and provides the headwaters of the San Marcos River. The water is a constant 71o year round, and probably the clearest, cleanest natural source of water in Texas. Although the water is 98% pure -- as pure as the water out of your tap -- is does contain various algae and microscopic plant/animal life, so it's not exactly drinkable, but almost. There is a lake at Aquarena Springs, Spring Lake, created by a small dam and fed by the springs, plied by the famous glass-bottomed boats.

Recently, Aquarena Springs has opened the springs for groups of divers. However, individuals may not dive in the springs without permission. Various Texas dive shops schedule trips to Aquarena Springs, and the management is very gracious and provides excellent facilities. We were pampered almost beyond reason, and enjoyed a wonderful January dive. Most divers choose to stay in the historic Spring Lake Hotel, a quaint inn dating from the 1920's, located right on the headwaters. The complete agenda includes dinner and lunch at Pepper's, the local hangout, but each dive shop arranges the specifics.

The two-dive package began with a gathering by the hotel at 5pm, Saturday. Six divers and the dive shop leader stood in the 45o misty cold, waiting for the glass-bottom boat to arrive from its pier, 100 yards away. Granted, hauling your gear 100 yards isn't a major problem, but, like I said, they pamper you! There is also a practical reason for the short boat trip: the destination is the inside of a faux hill, used for the mermaid shows, and the only other way inside is via a busy gangplank littered with equipment, compressors and other paraphrenlia. The fake hill is lovingly referred to as the 'volcano' by the employees.

The boat ride is short, but since it's a glass-bottomed boat, we get a good look at where we're going. The first impression is one of too much vegetation, but occasionally the plant life opens up and you can see "the bottom". Turns out that the plants grow about 1 inch per day, so it is an on-going battle to keep them at bay. Aquarena Springs even has a special harvester boat which trims the plants and collects the trimmings, which are then used for fertilizer on the grounds of the park. The park employees keep all the vegetation trimmed down to the bottom surrounding the high-powered springs, and around the more interesting low-powered springs.

Suddenly, we see a perch, a bass, and -- wow! -- an albino catfish! The more we look, the more life we see. But then the trip is over and we're at our destination. We offload the equipment on to the gangplank, and from there through a door to a changing room. This room is used by the 'mermaids' and other Aquarena Springs entertainers. What strikes you most, however, is the HEAT! They have the room at about 100o! And most welcome it is because we're thoroughly chilled. Steadily warming up, we're envigorated and quickly change into our wetsuits. The dive leader gets into his skins and 5mm suit, but quickly starts to notice that he is sweating. We all decide to leave the door open!

The floor of the changing room has an opening, showing the clean, clear water and a few fish. The bottom -- about 15 feet -- is covered with small rocks, but that's about all we can see. The opening is well constructed for entry and exit, with handrails and a platform for sitting, allowing a diver to put on a BC without having to exert too much effort. The Aquarena Springs dive leader says we can either slip into the water from the sitting position, or stand on the platform and 'big step' into the opening. To do the big step, you have to turn 90o as you jump. I was a bit surprised that all the divers decided on the big step entry. As each one entered, they all came within inches of bashing their heads on the side, but none did. And the 'big step' was just a little less than a boat-type big step: more of a 'little-step-and-a-half'. The Aquarena Springs leader instructed us to sink to the bottom to make sure we had enough weight, then watched each diver to see if they could obtain neutral.

The entry into the water was cool, but actually quite inviting after the warm-room-in-street-clothes turned into the overheated-room-with-wetsuit! My 3mm suit was quite adequate for the dive and I never got chilled. Upon reaching bottom, I looked up at the superstructure of the changing room/faux volcano. We were in the underwater arena, or stage, where the 'mermaids' do their show. There are several low-pressure air supply lines - superhooka's! - draping down into the stage area. These are how the mermaids breathe during the show. I picked one up and tried it. The end was a flexible rubber, almost identical to the filling station water hose: you push the tip to the side and the fluid comes out, air in this case. Using it to breathe was a little easier than a free-flowing regulator because there is no mouthpiece to get in the way. But it was still a bit disconcerting. However, I could easily imagine that one could become quickly accustomed to it.

It wasn't quite dark yet, but some of the divers turned on their lights. The Aquarena Springs dive leader motioned to us and we swam around the volcano; it was about 5:45pm. We exited the artificial stage area and found ourselves surrounded by a forest of six to twenty feet high water plants. The leader took us through an opening in the forest, and directly to our first look at a spring. The lake contains at least three fast-moving springs, and many areas of slow-moving springs. This first spring we saw was actually capped, with a large metal enclosure nearly cutting off the flow of water. A large diameter pipe then directed the water to an outlet near the stage area. This arrange ment ensured the stage area the clearest, cleanest water possible. Since it is illegal in Texas to complete cap off a spring, however, there was a basketball sized opening on at least one side of the box-shaped cap, and fast flowing spring water rushed out.

This fresh-from-the-Earth water was actually a few degrees warmer than the surrounding water, obviously due to the cold weather topside. In the summer, I'm sure it feels cooler than the surrounding water. Later on in the dive as we cooled down, I found a few of the divers welcoming the inverse thermocline by hugging the bottom near the fast-flowing springs.

It took a while to notice, but there was a very subtle current just about everywhere we went, and you found yourself having to adjust every now and then.

At first, I was a bit disappointed in the "wildlife" as we headed for one of the low-pressure springs. The water was a bit murkier than I had expected, and several of the divers exhibited a bit of trouble keeping off the bottom, clouding the water even more. I quickly decided that being in the lead was the best idea, and I tried to get my buddy to follow along. However, that didn't work out too well either, as my buddy was the worst offender. It proved to be a challenge to find any fish at all for a while. But, as we all settled down and relaxed, the water cleared up considerably and suddenly we realized the fish were all around. Darkness was now upon us, and the use of lights was no longer optional.

The perch and bass were everywhere, and there were schools of "fishbait", smaller fish that I couldn't identify. A spooky apparition suddenly was in front of us, a pure white 15 lb catfish! We eventually counted about six or seven of the albinos, said to be imported from Mississippi.

The Aquarena Springs dive leader took us to one low-pressure spring and pointed out the "bubbling", the appearance of the sand as the low-pressure water pushed its way out of the ground. Approaching slowly, you could stick your finger two or three inches into the sand where it was bubbling, and you could feel the warmer water seep past. It was quite eerie. Although the boat drivers will tell you that there are only certain locations in the lake where there are high- and low-pressure springs, I quickly discovered that - upon much closer inspection - the spring water bubbled from almost all over. To lift a small rock or two from the bottom would more often than not reveal a very small seepage point.

While I was inspecting the geology, the Aquarena Springs dive leader started lifting rocks, too, but he was searching for crayfish -- what I called "crawdad's" when I was a kid. These miniature lobster-looking creatures are the favorite food of the bass, and the larger specimens will come within a foot or two and wait for you to release the poor little bugger. Upon release, the crayfish would desparately swim at a remarkable speed for the safety of the rocks, but the bass was much swifter, and then -- gulp! Another friendly fish! After this first demonstration, we went searching gleefully for the hapless creatures. It didn't take long for the water to start to murk-up again, though. And, again, we slowed down our search to let the water clear up. Most often, though, we'd have to move on to clearer waters.

As we worked our way across the lake, the Aquarena Springs dive leader suddenly pointed toward the far shore, and we saw our first gar. The long, spotted gar was curious, but quite cautious, never approching closer than 20 feet or so. Our beams couldn't track him for very long. It was a little disappointing because we were told that they are much more accessible during a night dive, and that they hid out in the weeds during the day. But it was an interesting glimpse.

I wasn't around when the dive leader saw a huge prawn, about 12-14" long with a long stripe. Pretty amazing size, I thought, and almost called it a fish story, but some of the other divers saw it, too. The Aquarena Springs dive leader then carefully uncovered a few select rocks, and we had a fleeting glance at the snail darter. A few rocks later and we were rewarded with the sight of a sightless white salamander, unique to this area.

Soon, the leader had us ascend and call out our remaining air. Most were down to about 1200 lbs, so we started to head back. Still on the surface, we spotted several interesting birds perched in the trees surrounding the lake. I was still not cold, but the surface of the lake was decidely cooler than even 10 feet below. Surrounded by black water, spooky trees and unknown animals, a chilling breeze and only a shivering icyness awaiting me above, I slowly sank back into the warm, welcome, quiet peace of the inky waters. It was a great feeling to be so at ease in such an alien environment.

The swim back was a bit more direct, but we spotted another gar and several more albino catfish. The perch seemed to have all disappeared, and it made me think about what the boat driver had said: the movie "Piranah" was filmed in this lake, and the Texas perch were the "stand-in's" for the ravenous creatures. A little red dye for blood and a little movie magic (not much magic, however, as Piranah was definitely a 'B' movie) and the perch were the most feared underwater creepies this side of the monster from the lagoon. Maybe, like the actors who get a little too much into their role, they were hovering around, waiting to attack?

Unmolested, we finally found our way back to the volcano and one at a time floated up to the hole in the floor (ceiling?). Now the heated rooms were VERY welcome, and no one complained about the arrangements. By the time we were back in street clothes, we had finally warmed up, so stepping back into the cold wasn't so bad. Since our next dive was first thing in the morning, we left our equipment in the room which was then locked up.

With no equipment, we simply walked back over to the hotel, happy to get to the room for a hot shower.

The leader told us that a professor at the nearby University of Texas studied the area extensively and uncovered the remains of "Clovis Man", hunter-gathers who lived on the San Marcos River over 12,000 years ago. Many artifacts have been retrieved and are on display in the gift shop.

You can still see the archeological site on the bottom, covered with plastic and kept in place by bricks. Apparently, the professor died some years back. Some of the graduate students have done a bit of work on it, but there has been very little activity in recent years.

The next morning came too soon, as mornings often do. We met again at the headwaters in front of the hotel, shivering openly because it was about 38o. We were entertained by two nutria's, a mix between a beaver and a rat, with teeth and fur like the former, and a tail like the latter. A strange creature, quite at home in the water. The Aquarena Springs boat arrived shortly after 8am, and we again took the short ride, then into the volcano. On the way, we also saw some commorants, watched their almost submerged profile as they swim, and saw them diving under the boat for food. Upon entry to the changing room, we saw that the Aquarena Springs people had filled our tanks, so we were ready to go.

Suiting up was - as second dives usually are - a less enthusiastic group, still sleepy, and not welcoming the struggle into still slightly damp wetsuits. Actually, only one diver complained and it was his own fault for not turning his suit inside-out last night. Everyone else had a perfectly dry inside lining, thanks to the hot air that had circulated through the rooms all night. Most everyone's boots were still wet and cold though, but that wasn't too bad, and everyone started waking up.

The divers all suited up and got into the water quickly. The water seemed about 10 degrees cooler than last night, but I decided that it was my body temperature that was cooler, not the water. We quickly assembled and took off into the lake. The water was decidedly clearer, with visibility at about 30-50 feet, and orientation was much better for all the divers. It's amazing what a little sunlight will do for you! Most everyone managed to stay off the bottom better, too, probably because there were more reference points to see. We started as the night before with the capped spring. The warmth of that spring water coming off the side of the cap was even more welcome this morning.

The bubbling low-pressure springs were even more beautiful and strange, and it was simply fascinating to hover and look at them. Often I was compelled to gently place my hand into the loose sand and let it seep through my fingers. The inverse thermocline wasn't so bad, either!

We undertook the task of finding all the poor little crayfish we could; the bass were fat and happy that morning. As I approached the far bank, I was ecstatic to see a school of gar, only a few feet away. I managed to even touch one before it darted away. I followed them around for a while, and got into a staring contest with a big one. It won. But I was amply rewarded by the wonderful sight of an interesting looking fish.

We ended up seeing quite a few gar before we went back, belying what the Aquarena Springs dive leader had said. Once while skimming over a huge plot of the forest, we scared up a snapping turtle, which quickly glided away and hid. Moments later, I spotted a box turtle diving for cover, too. Searching for him led me to a huge sleeping albino catfish, about a 20 lb-er. It didn't seem the least bit interested in me, and very slowly moved deeper into the forest of plants.

We visited several other sites, each containing fast or slow springs, and one or two containing both (which, geologically, is supposed to be rare). We never ventured down near the dam which created the lake; the Aquarena Springs dive leader said it was nothing but vegetation. Over half-way into the dive, we again ascended to check our air. We looked over to the near bank and saw several people pointing at us, taking pictures. We laughed because we knew we were warmer than they were, even though we knew they thought we were crazy.

Overall, it was an enjoyable dive, very leisurely and relaxing, but still quite interesting. The Aquarena Springs people were all extremely friendly and helpful. Not only is Aquarena Springs the warmest water in Texas in January, but they have the warmest changing rooms in Texas, too! The changing room is what made it "doable", unless you LIKE being macho and freezing! If you live within 4 hours of San Marcos, I would recommend Aquarena Springs as a pleasant winter weekend dive. It certainly beats the heck out of sitting around a drafty old house, reading back issues of dive magazines!

Disclaimers: My fauna and flora descriptions are weak, at best, and I admit to not doing my homework. I only know there are supposed to be over 100 different forms of aquatic life in the lake. A lot of the descriptions and names were told to me, but as there is often a swift current between my ears, and they got washed out to sea. But as with most things in life, if I didn't get this posted right away, it might never see the light of day. So my apologies to those many of you who are ever so much better than I at fish ID and underwater biology. I promise to do better, next time. However, as fresh water dives go, this was a pretty good one, and certainly a great warm winter dive, as warm winter dives go, on the edge of the Gulf of Mexico.

Robert Laird
Houston, Texas

Story update:

Shortly after I did the above dive, Southwest Texas State University (there in San Marcos) took possession of Spring Lake and its surrounds. Standard diving has been prohibited there, but they now offer a Scientific Diving course. It's a two day course which focuses on The Edwards Aquifer, the Habitat, Endangered Species, Archeology, State & Federal Regulations governing Spring Lake and advanced diving techniques to ensure protection of this critical habitat.

To see some pictures of Spring Lake, jump to this web page:

To get more information about the Scientific Diving program from SWTSU, jump to this web page: