The Lost Secrets of Maya Technology

by James A. O'Kon

  Cenotes: The Path to the Sacred Water of the Underworld

  A cenote is a natural well extending down to the swift-flowing fresh water of the aquifer coursing below the surface of the Yucatán Peninsula. Clusters of these deep, natural wells are known as the Chicxulub ring of cenotes, first observed on NASA satellite images (Figure 8-1). The cenotes brought life-sustaining water to Maya cities built around the natural wells and enabled the northern Yucatán cities to survive longer during the Classic collapse. Cenote is a word derived from the Yucatán Maya word dzonot, which means “sacred well.” This word was construed by Spanish conquistadors into the word cenote.

  The technological challenge of engineering systems to provide a safe and comfortable lifestyle was not completely solved with a perennial supply of fresh water. The deep cenotes required engineering solutions to access the groundwater located deep below the surface. Engineering solutions ranged from steps carved into the walls of rock to wood bridging scaffolds leading down to the water level.

  The requirements of irrigation for agriculture and protection from floods due to torrential storm water from hurricanes and rainy season storms were challenges that were overcome by Maya engineers. Even in cities with cenotes as a permanent water source, water-management technology stepped up to prevent flooding, an essential measure to ensure the survival of the city. Water-management systems included sloping the roofs of buildings, patios, and the surfaces of other hardscapes in order to transport storm water away from residential areas. Storm water was then directed into agricultural fields, underground reservoirs, or natural depressions to serve as a reserve of water during drought. The roads in the city were designed to be part of flood control. Elevated roads diverted flood waters away from the occupied areas of the cities as well as offered pedestrians a dry walkway.

  Cenotes in the northern Yucatán come in a variety of sizes and geometries of the wells. Some cenotes are still being used today as potable water sources, and some have been turned into tourist attractions both for the pleasure of swimming in the beautiful waters (Figure C-18) and the opportunity to scuba dive into the water and explore the underground rivers coursing through the aquifer. Others have caved in and are filled with debris.

  Chultunes: Water Collection and Underground Storage Systems

  The majority of Maya lowland cities were located in areas without access to permanent water sources. Maya engineers resolved water-management issues with water collection and storage systems that went well beyond the construction of simple capture and containment systems. These complex systems were integrated into the planning and construction of the entire built cityscape. The cityscape was designed to utilize all exposed horizontal surfaces to optimize storm water acquisition and direct it into storage systems called chultunes. Chultune is a word combining chul, meaning “wet” or “becoming wet,” with tun, which means “rock” or “stone.” Combined, the words can be defined as “rock place that becomes wet.” The chultune-based hydrological system for a city was designed and constructed to capture storm water and direct the flow into the orifices of underground structural reservoirs for storage and use during the dry season.

  The water capture system included the design of urban structures with sloped roofs that diverted water into plazas and canals designed to transmit water toward the collection system of chultunes (Figure 8-2). The use of chultune-based water-management systems extended from Uxmal in the Puuc Hills to Uaxactún, located in the southern lowlands of the Petén. The concept of chultune water catchment and storage systems spread throughout the entire Maya zone. The chultune water capture system was designed to optimize the collection of water during the rainy season and store the captured water for an 18-month supply (Figure 8-3). Chultunes were excavated in the limestone stratum in many locations throughout an urban area. In some cities, more than 100 chultunes served the needs of the city. They were located under plazas, integrated into building designs, and situated in sloped collection terraces.

  Figure 8-2: Structural section and construction of typical chultun. Author’s image.

  The geometrical configuration of chultunes and their number and location were optimized to collect, store, preserve, and retrieve stored water. These reservoirs varied in size, but a typical chultune structure would include an underground containment chamber with a base dimension of 3 m × 3 m. The height of the walls of the reservoir from the base to the spring line is 4 m. The dome structure enclosing the top of the chultune is a truncated Maya vault structure encompassing the containment vessel. The access opening at the top of the reservoir is a cylindrical orifice constructed of concrete. This opening of the orifice is 1 m in height and .5 m in diameter (Figure 8-2).

  The ingenious engineering and construction of the chultunes structure is described in Figure 8-2 and Figure 8-3. The initial step in constructing a chultune was the evacuation of its structure. Excavation would extend through the shallow soil layer and into the limestone substrate. Excavation of the firm limestone created the desired rectangular volume that defined the containment structure. The construction of the containment vessel consisted of paving the floor with stone blocks and erecting cut stone walls with cast in place concrete placed between the stone and the excavation around the perimeter walls. The walls extended up to the spring line of the encapsulation dome. The roof was constructed of composite stone and concrete using Maya structural engineering techniques for a vault structure. The dome extended upward to the apex, where the cylindrical shaft of the orifice was constructed. The orifice shaft provided a minimum opening to reduce evaporation but permitted access for water vessels. The interior of the stone structure was covered with a waterproof stucco surface to prevent leaking.

  The number of chultunes varied with the population of the city, and their volume was designed to provide a sufficient quantity of water for the target demand. This demand required a city water supply for the six-month dry season, plus a factor of safety equal to a volume of 18 months of water supply to account for unexpected periods of droughts. This encapsulation structure for water supply was a brilliant design, and modern technology has not improved on the basic concept. In fact, modern fiberglass cisterns used in contemporary applications have a design similar to Maya chultunes. The volume of a typical chultune was 44,000 liters at full capacity. At the consumption rate of 3.3 liters per person per day, this satisfies the requirement of 36 persons for 365 days, or 72 persons for 183 days.

  Figure 8-3: Urban water catchment area with chultunes. Author’s image.

  Field observations and forensic engineering investigation of existing chultunes have been performed at several Maya cities, including Uxmal, Oxkintok, Labná, Chicanná, and Xtampak. Measurements of exterior structural portions were taken, and the exterior portions, including collection structures and the interior walls of the chultune, were photographed. Photographs and video of the interior of the chultunes indicated that the geometry and construction of these examples is quite similar to the classic design described. The dimensions of the orifices satisfied the classic standards and were similar; however, the depth of orifices varied with the site. The interior photos of the chultunes indicate smooth stucco coatings. Figure C-19 illustrates the masonry structure of the access orifice in a chultune at Xtampak.

  The Open Reservoir: Shaping the Cityscape to Optimize Water Capture

  The absence of a perennial water supply for the largest of Maya cities required an engineering effort on a grand scale. During the Classic Period, the world’s largest cities, like Tikal, Calakmul, and Edzná, employed similar hydrological solutions to satisfy the water-supply needs of their burgeoning populations. The large populations in the city, as well as in the hinterlands, required creative solutions to create a water-management system that supplied potable water for the city and irrigation water for agriculture. Their answer was to integrate the design and construction of all urban components, including the topography of the cityscape, the shape of the terrain, and the configuration of monumental structure
s and hardscape, into an efficient collection, storage, and distribution system required to produce a dependable water supply. Their concept was brilliant: locating the city on high ground, modifying the gradient of the topography, and optimizing roof structures to collect water, a process and implementation that evolved over a period of centuries (Figure 8-4).

  The large-scale, monumental architectural complexes were located on the summit of the hills and ridges. The buildings, the landscape, hardscapes of patios and plazas, and the elevated roads were designed as a system to collect storm water and divert the flow toward collection points. Reservoirs were constructed on the height of the topography of the central city, and along the sloped hillsides. In addition to the excavation of new open reservoirs, engineers took advantage of depressions in the topography that were once the quarries that supplied the stone for building the city. These recycled depressions and new reservoir sites were lined with clay, concrete, or stone walls, and stuccoed faces to prevent leakage.

  The water-management system controlled the flow of water using complex hydraulic engineering systems including dams, sluice gates, flood gates, and water-diversion systems, including elevated roadways and dikes. The engineering technology used in this system was based on the same principles as modern hydrological systems. Water-control mechanisms of the Maya system were enabled when the reservoirs were at full capacity during the rainy season. Water flow was diverted from the reservoirs and flowed past the full reservoirs into the agriculture fields and into low-lying wetlands. During the dry season, this ingenious system applied gravity to induce the flow of water to the agriculture fields lying at lower elevations below the reservoirs. Water could be supplied to the agricultural areas by opening sluice gates in the perimeter of the reservoirs, permitting water to flow downward into the cultivated fields.

  The water-management system at Tikal had a series of 13 reservoirs with a total capacity of 147,631,068 liters. Calculations indicate that this total volume would sustain the city for 18 months. This provided a six-month supply for typical rainfall and an 12-month supply for water shortage situations. The creation of this hydrology-based cityscape was a centuries-long endeavor using a large, well-organized workforce. Massive amounts of earth and rock were moved to shape the terrain that created this water-supply system. The efficiency of an integrated cityscape watershed system is determined by the volume of storm water captured, mitigation of seepage loss in the transport of the storm water, the size of the storage structures, and loss of water volume due to evaporation and seepage.

  Unlike the chultune system, the open-surface reservoir system was highly susceptible to evaporation due to the large area of water surface. Maya engineers minimized surface evaporation by planting water lilies in the reservoirs. The broad leaf of the prolific water plant covered the water surface in the reservoir and reduced evaporation. Additional advantage of the water lily plant included purification and filtering of the water supply.

  Figure 8-4: Design of urban watershed and collection system for reservoirs. Author’s image.

  Aqueducts: Maya Engineers Control Water and Create Public Space

  Maya innovation was at its best when resolving solutions for populations that required dependable sources of water and was equally innovative in solving issues of urban places with an excess of water. The ancient Maya city of Palenque is situated in the hilly rainforest of Chiapas. The city was founded on a plateau with natural features of the terrain marked by hills, deep gullies, and sheer cliffs. The site had a surfeit of natural water courses flowing across the center of the city. The natural water sources included nine waterways fed by 56 springs. The city of Palenque is named after a nearby town; however, the original name was Lakamba, meaning “big water,” because of its numerous water courses.

  The natural sources of water, although providing an adequate supply of water for the population, had a negative downside. The rainy season storm water combined with the natural flow resulted in the flooding of the city. During the rainy season, 47 percent of the annual rainfall, amounting to a total of approximately 1 meter of rain, fell during a four-month period. The massive rainfalls caused the streams to overflow, as storm water rushed down the steep slopes from the hills and combined with heavy storm water falling on the level cityscape. The expanding city required extensive flood control measures. In addition, the open-channel water courses traversing the city center created impediments to the construction of buildings and expansion of the urban center of Palenque.

  Maya technology solved the multi-faceted urban water issues with the construction of an underground aqueduct system designed to collect water upstream of the city center, and transfer the water under the city center and into the Otulum River downstream of the city. This ingenious underground hydraulic system controlled water flow and created a flood-free urban space. The channels of water that flowed through the city center were captured, controlled, and buried in vaulted, structural concrete conduits. This engineering application allowed the expansion of plazas where none could have been built before. This hydraulic system combined urban planning, hydrology, hydraulics, vaulted structures, and technical innovations to achieve the solution (Figure 8-5).

  The goals of the engineering effort were to control the flood water by constructing subterranean cast-in-place concrete aqueducts to control flooding of the cityscape and to create public space for growth of the urban center. Maya engineers created new urban space on the level plateau; the new flood-free area was then paved for plaza space. Additionally, the steep slopes of the hillsides were terraced to create level building platforms for urban structures. The terracing of the hillsides slowed and controlled the flow of rainwater into the plazas.

  It is apparent that Palenque engineers understood the principles of hydraulic engineering. They used the aqueduct system to generate positive water pressures in the palace (Figure 8-6). The aqueduct line buried adjacent to the palace extends in a north-south direction and is parallel to the east side of the palace. The aqueduct was constructed with a steeper grade when approaching the palace in order to increase the speed of water flow. The shape and area of the aqueduct was reduced at a point underneath the palace. The reduction of area in a conduit will increase the velocity and pressure of the water in the smaller conduit downstream. The increased pressure creates what is termed a “head of water.” Hydraulic analysis of the water flow and geometry of the aqueducts indicate that a head of water equal to 6 meters was generated. This pressure indicates that water can be raised to 6 meters in height above the aqueduct producing sufficient positive water pressure to induce water flow into the palace. This pressure would permit the flow of potable water for drinking, domestic uses, toilets, and fountains in the palace. As can be imagined, running water was a luxury, and locating a hydraulically engineered system adjacent to the palace would be an appropriate location. Ceramic tubes, suitable for piping, have been encountered at other Maya cities, including Edzná. Though the systems for increasing water pressures are evident at Palenque and toilet spaces have been identified in the palace, the piping system at Palenque has not been found.

  Figure 8-5: Diagram of structural, hydrological, and construction details of typical Maya aqueduct. Author’s image.

  Figure 8-6: Photograph of interior of existing Palenque aqueduct. Photo by Kirk French.

  Maya Technology Increases Agriculture Yields

  As the Maya population, grew the demand for increased agriculture yields became a constant challenge that had to be satisfied. Higher crop yields meant a demand for more water. Maya water-management technology met the challenge of that demand with a multidiscipline effort to generate abundant agriculture for the needs of the Maya population, plus a surplus for trade. Their interdisciplinary approach to solutions included combining the principals of hydrology with agronomy to increase agricultural output. The Maya had practiced agronomy for millennia. Those innovative agriculture technicians developed maize from a native grass more than 8,000 years ago. The type and variety o
f cultivars increased as the Maya agronomists entered their Classic Period. Technological innovations enabled the population to expand at a rate that outstripped capabilities for feeding the populace using traditional agriculture methods. Agriculture technology made a significant contribution to their ability to produce larger quantities of food. They developed sustainable long-term growth strategies for agriculture systems including replenishment of soil, irrigation and fertilization, cultivation of hillside terraces, canals, raised fields, wetland agriculture, irrigation dams, and a diverse aquaculture.

  The only solution was to depart from tradition and develop new methods to increase the agriculture yield. Traditional farming methods included cultivation of plots using the slash and burn technique. This method of cultivation produced a low crop yield because of the thin soils of the Yucatán and the long-term cycle of reclaiming depleted agricultural plots. Slash and burn, or swidden agriculture, requires cutting down a section of forest and burning the cut vegetation. The ashes provided nutrients for the soil. However, the soil becomes depleted two to five years after the initiation of the cycle. The land is then planted as an orchard and allowed to return to its natural growth. This may take a period of five to 15 years. In the meantime, new land is cleared and burned, and another cycle begins. Maya engineers combined technology and proven cultivars to increase food supply by creating new fertile land areas including the use of reclaimed wetlands, terraces, raised fields, and new irrigation methodologies.

  Terraced Fields

  Regions teeming with large populations turned to the integration of civil engineering and agriculture technology. The use of sustainable agriculture terraces was introduced to areas that had hilly terrain with a minimum of flat terrain for agriculture use. Terraces were hydrological structures that were constructed on a sloped hillside. Initially the level or bottom land areas were cultivated. As the demand for additional food supplies increased, additional arable land was required for farming. Agriculture terraces were then planned, designed, and constructed on the hillsides above the bottom land. The use of agriculture terraces served multiple purposes, including increased area for cultivation, reduction of soil erosion, and capture of water for use in the dry season.