Cave Survey Mexico

Sacred Cenote

After what we could call the rainiest days of the year we decide to get a bit more wet…

Our surprise is when we actually step to the edge of the entrance pool at Taj. The water is more than a foot higher than normal and very tannic;it was expected but always a surprise to see the impact of the rain on these complex water reservoirs.

In a report published on the web titled TEN YEARS IN THE MAYAN CAVES by J. Neves and Ch. Thomas we can read some very interesting information on hydrogeology and karstology. I will keep this subject for another post.

So far our dive plan takes us to the cenote Sagrada, on the downstream section of Tajma Ha. There is some flow and visibility is far from excellent. Although our navigation involve a few jumps we aim at a conservative gas management.

One important detail is the fact that we are not surveying today, it is what could be called a scout dive, to get to know it before we enter there with tape measure and all the survey protocole we so far have been successfully using.

Also, a good idea just to get together and dive just for the pleasure, pure pleasure!

After a bit more than twenty minutes we reach open water, the first surface access, few hundred feet from the actual cenote entrance. Water is tannic and the cavern zone is full of bats flying around our heads and no, not sucking our blood!

A short incursion on a side jump line takes us towards smaller passages of Taj the line that goes to Twin Cenote and after couple of jumps we end up in ever small cave in direction of City of Agra…How is that for directions! Thanks to Alan who knows Taj like the back of his right fin! For a short distance it takes an allure of a Nohoch like cave, with brown sediment/silt on the floor and white walls and nice formations but this is short lived as it pinches down quickly and get into real sidemount passages.

With all this mind-mapping taking shape we decide to turn the dive and make our way out of this small and unstable like environment! At some passages, where restrictions made a close to zero visibility, swimming out obviously takes a bit longer than swimming in and proves to be a learning curve for going into small passages. One of the reasons for me to take my time at pushing my comfort zone is to look, listen and feel. A bit like a primary assessment you know what I’m sayin’?

On the way out we did notice that the water level at the main cave entrance had lowered already, so in a little over an hour dive, the fresh water layer was already pushing down the slat water layer… A bit of science that will be talked through in a future post.

All in all it was a great dive, great buddy and lots of work still ahead of us!

Dive profile:70′ @ 42 feet

On the road again…

On a rainy morning, after a good breakfast, Alan called me to go diving again! It may sound as if I am complaining but rest assured I could do this for the rest of my life!
Today we decided to work on the ‘jump’ side of the circuit and try to survey up to the T at the GL in Jumna Passage. It should be do-able but none of us have gone that way before so we don’t really know what to expect! As a general rule in cave diving, you start by diving all the lines accessible up to thirds, starting with the main line. That is called progressive penetration and is a very effective way to get to know the cave before you can start planning some more complex dives. So we kind of bent that rule a bit by starting a survey on an unfamiliar line but as it is a popular circuit for cave training, it can’t be too challenging  so we still agreed on caution as usual.

The jump to this circuit is located just before the first big boulder, to the left. It is not that easy to see the line you jump onto because of the halocline but just go left and you’ll find it! The jump line needed to be surveyed too so I limit the amount of tie-offs and try to ‘aim’ as straight as possible. And off we go into our ‘pool out – reel in’ routine and make good progess until the passage start to get a bit smaller and windier. Some stations are just ‘placement’ and short distances too. As it is, it actually took us longer than when we surveyed the Gold Line with its long sections! At one point we are in a passage with a perfect flat and bright white ceiling with dark brown speleothems, cave formations, looking like columns holding the whole place so we can swim through, it is quiet nice in a way!
Along the way Alan spots a passage that looks like a sidemount line (not on the map!) in a garden of stained carbon calcite rock, a bit like if it had been in tannic water for a while, enough to get impacted by bacteria making the place spooky! Me and my backmount configuration feel rather good not to have to go there for the moment! Soon after, the cave opens up into a high ceiling room with some good size boulders followed by a halocline in some sort of a beding plane, not tight at all but flat ceiling, far out side walls and the ground is of some lunar landscape with its waves of very fine silt and rocks sticking out a bit everywhere.

The Shajahan Line

This is one thing that strikes me! The way the cave lays out its arms and other fingers so the cave explorers can lay line and shape the cave route! It seems almost surreal that Nature thought about us, one day, adventurous enough to stick our heads underground and  remember to leave on its path the so famous ‘Stations’ that are so important in a survey…Thank you Mother Nature!

I like when a plan goes without a hitch!
We make it to the T just on time to turn our dive, happy to have accomplished a constructive step in our survey project. We are couple of stations from the T on the Jumna Line and after the T there is a short section of GL then it turns into knotted line! Soon enough we’ll be starting from Buena Vista!

Out of the water we found the car park of Taj completely packed with cars, taxis and other vans… Just never seen it like that! We are wondering what or who may have caused this sudden interest!

Total dive time: 100′ @ 14.5 m

The Hall of Giants

So we started the ‘big’ section of the cave today, it’s called the ‘Jumna River Passage’. For those of you who know Tajma Ha, this name should bring to memory huge rooms, long swim and the beam of your dear and powerful HID light getting lost on the way!

The Jumna River Passage

We did a great job today, it went as good as last dive. Only one thing was a bit tricky, it was the longest section between two stations. A whole one hundred and fifty five feet and our meter only goes to one hundred and sixty five feet…Pfff! That was a long section and we turned the dive not to long after this passage. In fact we surveyed until ‘The Constrictor’ section took the next compass reading and turned the dive.
A little recap before going any further is that on the way in, Alan decided to pass by the ‘Chuck Deco Line’ so when we arrived back at the jump to get back out, he asked me (in a funny way!) if I was ok to survey this section. After I swallowed a mouthful of water I reply by the positive and we went out along the CDL while in survey mode!
Rest of the dive went smooth and did our deco and played around with our knobs and valves (nothing dirty though!) and exited the water, a bit cold.
Dive profile:105′ at 44 feet (on air)

Tajma Ha Survey Project

Survey Team:
Alan Formstone and Jason Renoux

Cenote Tajma Ha aka Tajma Hal

Today was our first real survey dive. Alan came to my house to pick me up and take us to our first stop – the filling station. There Alan took his sidemount tanks and I got my doubles and a safety tank as I was going to be in ‘solo’ mode for most of the dive.
At the gate in Taj we still had to pay the entrance fee and decided we needed to talk to the landlord to see if he’d let us in for free, for the duration of the project.
We met him on the way to the cenote, he was clearing up a quad bike trail.
After due introductions we agreed to meet at a later date when he’d have a CD with images of “a” map and the contact details of the last team of explorers…How cool is that so far?
At the parking lot we made our way through a few recreational divers (smoking before their dive!!) and Alan rigged up his tanks on the back of his car, while I used the concrete table for my doubles and safety tank.
The dive plan was simple but not without any “risks”! A better air management plan is decided and communication kept to it’s strict minimum. It will be appreciated later, you’ll see!
When I say “better” air management plan I mean we stick to thirds but as we are not really doing a long penetration we agree on monitoring our consumption every 2 or 3 stations in order to recalculate our thirds: “always keep 2 thirds for thejourney back.”

Once in the water, time for our gear check and dive plan review and this is easy as we are going to survey the main line (Gold Line) going towards a section called City of Agra. At each station (tie-offs) we’ll take the depth, azimuth and measure the distance between each of the tie-offs.
This is the basic survey to produce a basic map for any flooded cave. We will have to come back and do again some more measurement but this time taking the distance between the walls (left, right and ceiling) at each station.
For more accuracy we have to survey the line from the open water by the drip-line of the cave. So I tie the primary reel the closest possible from these points. That is where you realize that there is no tying point where and when you need them the most!
After couple of correction in laying the line we reach the permanent line. We had decided to survey the reel line on the way out.

The Gold Line aka Mumtaz Line

Now start the process of taking the data for the survey.

I hold the loose end of the tape measure, swim to the next tie-off while Alan position himself by the first station and takes notes. It goes flawlessly as we enter into a “routine” of pooling out, reeling in, taking azimuth (bearing) and depth, like a well served team! We must admit our joy about this outcome because, we both, as the survey started realized that we didn’t agree on any sort of communication whatsoever on how it was going to take place!

A little surprise awaits us when we reach a huge boulder that creates quiet a slop in the line that we decide to consider the top of it as a station in order to give the computer the room for calculating the height from the previous station. So many headaches caused while trying to understand Pythagoras and his mates…
Halfway through we reach the air dome, where we surface to have a quick chat. We do realize that air consumption is going crazy doing all this data collection so we agree to stick to our plan and get going as we both want to reach the ‘jump’ to the City of Agra line before we have to turn the dive!

The time spent surveying the line until we finally decide to turn the dive comes quick and, as planned, we still take the survey of few side connections as the software used for plotting the map may consider these gaps as errors, so we lay a jump reel (with Knotted line, thanks Alan!!) and survey this line to the secondary line into other passages of the cave.

Done! We head back out, take the survey of the primary reel line, do our deco stop and surface, not without a chill!

Dive profile:13.5m max, 119 minutes on air (maybe considering Nitrox for the coming dives!)