The Exploration of the Mayan Underworlds

By Christophe Le Maillot

The “Mayab” was regarded by the ancient Mayan as a sacred landscape.  For centuries, this great civilization flourished from what is now the Yúcatan Peninsula in Mexico to the Republic of Honduras.  Great cities such as Coba, Palenque, Uxmal and Chichen Itza were built near natural wells, or cenotes. These cenotes not only held important religious and sacrificial significance for the Maya, they also played a very practical and critical role in their daily life. In this hostile and harsh tropical environment, the survival of the population was directly linked to obtaining quality water.


The Yúcatan Peninsula is, in fact, a 250 square kilometer limestone plateau, with freshwater flowing underground and virtually no visible surface rivers.  The water table is accessible only by the thousands of cenotes or karst windows dotting the area.


Today, cave exploration efforts in Mexico’s Quintana Roo and the Yúcatan face challenges very similar to those facing the ancient Mayan hundreds of years ago. The remote access of many cenotes is still the main reason why 90% of all possible water-filled cave passages have yet to be explored. Here, the dense tropical brush creates a mighty adversary, one that can quickly transform travel into a dreadful experience. As a result, trail blazing is usually the first work completed before any cave exploration project can begin. Moreover, the irregularity of the karst terrain further augments the difficulties attendant to securing working access to an exploration site. In many cases, cutting a simple footpath is not enough. Long exploration projects require transporting large amounts of equipment over longer distances, which, in turn, require the use of horses and/or donkeys as load bearers. This requires that trails be cut with certain specifications in mind, for example, that they be wide enough for a fully loaded donkey to navigate through them. If one fails to consider logistical questions of this nature, disaster can strike quickly and unexpectedly. For example, during the 1999 Ox Bel Ha spring project, the hand wheels were left on the tank valves during transport. Though in a few specific spots the trail narrowed, it was initially thought to be of no consequence. This perception was revised, however, when a tank knob scraped a tree trunk, gas started escaping freely, and the donkey carrying it went on a rampage. We were very fortunate that nobody was hurt and little equipment was damaged. When negotiating challenging terrain as this, attention must be given to even the smallest detail.


Once trails are properly established, a base camp needs to be set up. The area cleared for the encampment should not be located too close to the rim of the cenote. The idea is to minimize the project’s environmental impact and to protect the delicate natural balance in existence.  Camp usually consists of a few wooden frames covered by heavy-duty nylon tarps that act as roofs. Under the largest one, there is a sleeping/food quarter on one side and a workshop/battery charging section on the other. The compressor and Nitrox filling station stands nearby, but closer to the water’s edge. The noisy generator is banned from base camp and is located further back in the brush.


Two days are typically necessary to transport the required equipment to a remote site like the one used during the Ox Bel Ha project. From this site, and for the duration of the project, a team member will regularly have to return to town to replenish the team’s food and water supply.


Encountering a dry cave section first can sometimes complicate access to the water. In such a case, carrying equipment to the water’s edge entails broader challenges, especially if that section is restricted or unstable. However, most of the time, in the Quintana Roo area, entering the water requires a minimum of effort; access is from the cenote’s ledge. However, further back inland the water table drops down considerably, and the distance separating it from the surface creates impressive vertical shafts. There, rappelling down, sometimes as much as 30 meters (100 feet), is not uncommon.


The typical cave environment encountered in Quintana Roo is marked by certain distinguishing characteristics: shallow depths, extensive passageways, speleothems, warmer water, and multiple entries. Most of the caves, even those lacking a direct connection with the nearby Caribbean Sea, show signs of its influence. These caves are said to be anchialine caves, one of whose most predominant characteristics is the halocline. Below this mixing zone of fresh and salt water, the salt-water layer has a very corrosive effect and often gives rise to deeper cave passageways. Also, though the lack of hydrostatic pressure generates little flow throughout the cave, alteration in weather patterns, smaller cave passages and freshwater vents into the ocean can induce an increase of flow. Lastly, percolation can sometimes be pretty heavy.


As a result of these almost perfect diving conditions, and of the promise they offer for cave exploration, over the years, numerous cave divers have attempted cave exploration in the Yúcatan.  In reality, however, there is more to cave exploration in the Yúcatan than simply “laying a little line;” it requires a true understanding of the cave environment.  Maze-like cave systems with a wide distribution of restricted areas and tunnels demand excellent navigational skills, refined in-water technique and mental toughness. They will undoubtedly challenge even the most competent.


In order to extend exploration to and beyond narrow bedding plains and other restricted passageways, side-mount techniques have been found useful and adopted. Side-mounting, however, should not be confused with solo diving or seen as an entertaining means of configuring equipment. Rather, it is an advanced cave diving practice that offers a reliable and different approach to distinct exploration scenarios.


Individuals involved in area projects must be self-reliant, focused and capable of working in a team; teamwork is the key to successfully completing any cave exploration. In such an environment, every team member contributes his own field of expertise, from local woodcutters to the programmer who creates the mapping software. Each one’s contribution to an on-going project can be measured by the daily progress of the exploration. Gathering such a group of skilled, dedicated, and team-oriented individuals is undoubtedly difficult; it takes time and patience to produce.


The focus of cave exploration, of course, is discovery. There is nothing more exciting than probing the unknown, than trying to figure out what lies past the next boulder choke. What is even more remarkable is the fact that even today, exploration, especially in Mexico, is still at an early stage. During the past twenty years, area cave explorers have surveyed and mapped over 200 miles of submerged passageways.  Their contributions have have helped to establish an extensive database. Three cave systems, Nohoch Nah Chich, Ox Bel Ha and Dos Ojos, account for 55% of this total. Without any scientific studies, reports or analyses, the importance of this exploration work can sometimes go unnoticed. However, over the last few years, biologists have identified 37 troglobitic species in theYúcatan (35 crustecians and 2 fish), discoveries that justify the excitement of the initial exploration. Furthermore, hydro labs and data loggers left in these caves are now capable of providing us with valuable information: tidal fluctuation, flow rates, salinity, turbidity and water temperature.


In this rapidly developing coastline it is important to persist in exploration efforts. A constantly growing population, coupled with a lack of a local infrastructure to accommodate it, is threatening the precious freshwater supply. The risk of contamination here is great given the porosity of the karst; from garbage dumps and disposal wells, pollutants seep through the limestone bedrock to the water table below.  Bringing the local community to an awareness of the aquifer and to the role it plays in providing it with quality ground water hopefully can bring with it responsible environmental action. The exploration and study of underwater-filled caves can play an important role in making this happen.


Like the ancient Mayan centuries ago, soon we may also find ourselves in a struggle to find quality water.


©DirQuest Vol. 3, No. 2 - Summer 2002



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