They significantly increased the area of available cultivated fields by altering the geometry of the hillside topography from its natural slope to the stepped configuration of the terraces. The terraces reduced erosion. Prior to altering the hillsides, the land was naturally sloped downward, permitting storm water to rush down the slopes, which caused erosion and flooding of the agricultural areas at the bottom of the slopes. The storm water slowed as it flowed across the level section of the terraces. This water was absorbed and stored by the deep soil fill retained by the terrace walls and used to irrigate cultivars during the dry season.
The terraces were planned to optimize the development of level, arable land as they stepped down the slope. The vertical stone retaining wall structures that created the stepped terraces on hillsides were founded on limestone bedrock. The walls, known as gravity retaining structures, are constructed of cut stone masonry and are wider at the base than the top of the wall (Figure 8-7). The width of the base is one-third of the height of the wall. The walls are backfilled with soil that extended to the top of the retaining wall and is level with the base of the uphill retaining wall. This geometry developed a triangular volume of fertile soil backfill. The terrace system had a great advantage over typical level ground agriculture. The Maya farmers used innovative soil re-building methodologies on the terraces, including growing cycles interspersed with carbon and nitrogen deposition via cyclic burning and flooding.
Flooding of the terraces was accomplished by two methods: The most common was the yearly deluge during the rainy season. The second, in areas that supported up-hill reservoirs and canals with water-regulation gates for controlling irrigation water, was the opening of the gates to permit water to pour down to the terrace structures. The stored water flowed down the terraces and recharged the moisture in the soil.
Raised Field and Wetland Agriculture
Wetland agriculture was extensively practiced by Maya agronomists. Bountiful crops were grown in marshes and wetland regions where food production was otherwise impossible due to the presence of standing water. Maya agriculture technicians constructed and managed a wetland-based agro-ecosystem throughout the realm. In some areas, 40 percent of the land is based in wetlands. Taking advantage of this swampy land provided the Maya with an expanded food supply. The agro-ecosystem included the design and construction of canals, raised field platforms, and aqua-farming. The canals and raised fields were one of the concepts developed to cultivate crops in conditions of low-lying marsh land and water accumulation caused by the heavy rainfall. The canal and soil platform systems were techniques developed by Maya engineers that increased agriculture production in conditions that prohibited the use of traditional farming.
The efficient canal and raised field systems were laid out and constructed in a Cartesian grid pattern. The canals followed the grid pattern and transcribed the limits of the rectangular raised fields. The canals were excavated down to the bottom of soil levels, and the soil was placed within the grid of the canals to elevate the surface of the interior into platforms by mounding the excavated soil to create a planting surface between the canals. Additional, borrowed soil was added to the raised fields to an appropriate level that kept the roots of the crops above the water level. The bottom of the canals was often sealed with clay to prevent the loss of water (Figure 8-8).
Figure 8-7: Section of terraced field agriculture system employed by the Maya. Author’s image.
The plots developed by the platform were planted, and cultivars were produced and harvested. As the cycle of crop growing progressed, soil eroded from the raised fields and flowed into the canals. This eroded soil became mixed with organic matter from the spoilage of animal, plant, and aquatic life living in the canals. Maya farmers maintained the canals and fertilized the soil by removing the rich sediment from the bottom of the canal and then placing this enriched nutrient on the surface of the raised field structure to rebuild the soil. This sediment increased the nitrogen level, which produced high yields of crops four times that of fields farmed using contemporary methodologies. The raised fields were further enriched by creating a compost of the crops, which remained on the soil surface after the harvest.
The agro-ecosystem of canals and raised fields proved to be a long-term strategy for feeding the population and enabled an added advantage of producing two crops per year. The increased yield would be raised with one crop planted on the surface of the raised fields during the rainy season, and another crop would be grown in the muddy and nutrient-rich bottom of the canal during the dry season. Canals or artificial water courses had other purposes as transportation routes for canoes or defensive moats. Canals supplying the water were also used as aquaculture systems: growing turtles, fish, amphibians, and vegetation that supplemented the diet of the Maya.
This great source of fertile land and ample water supply was exploited by the Maya culture and became the most productive agricultural source in the lowlands. With the aid of satellite imagery and remote sensing, researchers from George Mason University and the Geological Society of America have discovered a vast area of raised fields in northern Belize. The satellite images indicate a massive grid of raised fields more than 100 kilometers in width. Research has indicated that raised field agriculture was widespread, with 40 square kilometers identified in Quintana Roo.
Figure 8-8: Diagram of raised field and canal agriculture technology. Author’s image.
Maya Water-Treatment Systems
One can easily envision the condition of rainwater stored for six months in the static and closed underground reservoir of a chultune. The water has not only lost its freshness and has become vapid, but the lack of oxygen in the closed chamber creates a state of turbidity and becomes the perfect incubator for the growth of pathogens. The storm water collected in the reservoir had flowed across open surfaces, and there was always a high probability of bird feces being flushed into the containment structure. The stored water would have become aerobatic due to the lack of oxygen. In short, the water was distasteful and unhealthy.
Maya technology developed filter techniques to provide clean, potable water from stored water for cities that depended on chultunes and reservoirs. Water-treatment technology utilized two methods to provide clean water, based on the type of storage. These include the application of organic methodologies for water stored in open reservoirs, and microfiltration for water stored underground in chultunes or other storage systems that required filtering to clean the water.
Biological Water Treatment Systems
The natural, biological treatment processes utilized water lilies planted in the large open reservoirs. This decorative plant contributed to both the preservation and filter treatment of stored water. The wide leaves of the plant floating on the surface reduced evaporation by providing a surface cover and shade to prevent algae growth. The stem and root system of the water lily recycled organic waste; these plants produce and enrich dissolved oxygen into the stored water. They provide a microenvironment for numerous invertebrates that ensure extensive natural purification. The plants are suited for absorbing nutrients through their roots and storing these nutrients in their leaves. The stem and leaves in the water plants prevent sedimentation and provide a substrate for the growth of beneficial microorganisms. Frogs, dragonflies, and salamanders that controlled mosquito larvae will multiply naturally. The animals, insects, and water lilies integrate to form the natural biological treatment center engineered by Maya technology. Water lily plants could be also harvested and used as natural fertilizer in agriculture. This natural biological process produced a source of potable water for large populations.
The use of water plants in natural, biological water treatment centers has been introduced into contemporary water-treatment centers. The concept is now being used for cities with populations of 100,000. Modern water-treatment plants use aquatic plants for their ability to absorb pathogens, metals, and other contaminants from water. It appears that Maya technology applied a system that contempor
ary environmental engineers have discovered is economical and environmentally suitable.
Microfiltration Process For Clean Water
The majority of Maya cities did not enjoy the opportunity of using natural biological treatment processes in open reservoir systems to provide a dependable source of clean water. The majority of large Maya cities in the northern and southern highlands depended on chultunes for water storage during the dry season. Water stored in the underground structured reservoirs was subject to turbidity and the growth of pathogens. When water was distributed from chultunes, it was clouded with sediment and pathogens. This water was not safe to drink. Again, Maya engineers turned to the most abundant materials available to the culture, the same material that absorbed their rainwater and was used for fabricating cement and masonry for building these grand cities. They used the karstic limestone underlying the Yucatán shelf and exploited the porosity of this multi-purpose material to fabricate high-quality water filters.
The limestone could be shaped into various geometries to serve the purpose as a water filter. Karstic limestone has up to 40 percent porosity in its mass, with pre-sizing from 0.20 micron to 6 micron. This material qualifies as a microfilter using modern water filter standards. Water collected from a chultune would be processed using a limestone filter. Two types of limestone water filters fabricated from limestone by Maya technicians have been identified as part of the water-treatment system:
1. A limestone cylinder with a cone-shaped, truncated end that is used with an exterior reservoir of turbid water (Figure 8-9 and Figure 8-11). Turbid water entering the filter at the top was processed in the limestone and clean water flowed from bottom.
2. A cone-shaped vessel of limestone with an interior reservoir for turbid water. The interior reservoir permeates turbid water through the porous limestone shell. This process converted turbid water into clean water that flowed from the bottom of the filter vessel (Figure 8-10).
Figure 8-9: Cone water filters at Chichen Itza in 2004. Author’s image.
Figure 8-10: Maya water treatment filter with internal reservoir. Author’s image.
Figure 8-11: Diagram of cone filter filtration process. Author’s image.
Tests of the limestone water filters indicate that 1 to 2 liters per hour can be processed by a single filter. Each filter would yield 24 to 48 liters per 24-hour period.
Artifacts of Maya Water Filter Technology
Examples of Maya limestone water filters have been encountered at various sites and in collections. Examples include the solid limestone filter and the hollow water filter vessel. The solid limestone filter has been encountered at Maya archaeological sites. The elongated, cylindrical-shaped filter has the characteristic truncated cone configuration. Figure 8-11 indicates this shaped solid limestone filter. The hollow water filter vessel has been observed in museums and on historic sites. At Chichen Itza, the solid cone filter stands as an architectural mystery. However, it is possible that the role of the solid cone-shaped filter once played an important role in the life of the city. The subject structure is located to the north of the plaza between the Castillo and the Sacred Cenote. John Lloyd Stephens and Frederick Catherwood first related their observations of Chichen Itza and this structure in their 1842 volumes, Incidents of Travel in the Yucatán. The structure is noted as a “ruined mound.” Later records indicate that Doctor and Mrs. Le Plongeon excavated the “ruined mound” and uncovered a platform with stairways on each facade. Their excavation trench exposed more than 100 cone-shaped limestone artifacts. The Le Plongeons had the cones unearthed and laid on the ground outside the mound. These cone-shaped artifacts gave the platform its initial name, “the platform of the cones.”
Figure 8-12: Excavation of Platform of Venus with cone water filters. Image in public domain.
In 1889, while working at Chichen Itza, Alfred Maudslay photographed “mound 14” with the platform in the background (Figure 8-12). In the foreground, the limestone cones have been arranged in a line at the east side of the platform. Maudslay reported that the cones were unearthed by the Le Plongeons. It is unknown when the name of the structure changed from “mound 14” to the “platform of the cones,” but it held that title until it was changed to the “Platform of Venus.”
Today, at Chichen Itza, the cones are stacked like artillery shells in a fenced enclosure adjacent to the Venus platform. They are mysteriously aligned with the main axis of the platform, biding their time to reveal their true role in Maya technology. The facade of the Venus platform displays bas-relief carvings of the diving god “Venus,” as well as a number of water-related motifs including the water lily, turtles, and fish. It would appear that the platform had a strong relationship to water and possibly represented the power of the water lily lords.
The mysterious cone-shaped artifacts are obviously limestone water filters. A field sketch by the Le Plongeons indicates an organized stacking of numerous limestone cones buried in the core of the platform. It is arguable that this structure was once used as a water-processing facility to filter turbid water from cenotes. The water in the Sacred Cenote is notorious for its turbidity and the location of the platform is suited for water transfer. The facility had been decommissioned as a water-treatment center, and the cones were buried below the platform prior to the modifications to be used as ceremonial platform. The “orphan” limestone cones are now positioned a few feet from the platform structure. They are near their Maya burial site, as if waiting for a visionary archaeologist to identify their true function, which may have been filtering water to preserve the health of the population of Chichen Itza.
9
The Maya Interstate Highway System
The commercial and political success of Maya city-states was dependent on their ability to efficiently maintain the flow of communication, commercial trade, and the movement of traffic between city-states. Their ability to travel between strategic destinations was dependent on the condition of overland routes. These routes, once limited to winding jungle trails, left travel conditions at the mercy of the capricious natural environment.
The vast majority of the 125,000-square-mile Maya realm consisted of rough natural terrain, overshadowed by the dark rainforest canopy, overgrown with tangled roots and covered with slick, green moss, making travel difficult in any weather condition. During the long rainy season, copious amounts of tropical rainfall made travel on the rutted soil tracks difficult for the typical traveler and nearly impossible for the cargo porters straining under back-breaking loads.
Maya technology was challenged to develop a creative solution that would overcome the reliance on rough jungle trails. These routes retarded travel in the best of weather conditions and became a quagmire of torturous proportions during the rainy season. Maya creativity rose to the challenge of travel routes that restrained commerce and hindered the power base of the city-states. The solution was an all-weather road system that facilitated the flow of goods, communications, and the swift movement of military traffic, while enhancing political and economic relations between polities.
This innovative roadway system was developed around 300 BC and spread throughout the realm. Maya call these roads sacbe (plural, sacbeob), which means “white road,” referring to the white color of the road pavement. The road systems were constructed well into the late Classic Period and used for centuries in the Post-Classic Period with little maintenance. Examples of these roads have been observed throughout the Maya world, and they represent a significant investment in capital resources and human labor. Their construction and application were an important element in the Maya system of politics and commerce.
The Design Criteria for the All-Weather Roadway System
The Maya power elite, when faced with a transportation dilemma threatening the growth of their wealthy and powerful city-states, began the search for a technological solution. The transportation of commercial goods, military movements, communication, and other travel purposes could not operate on the treacherous jungle trails.
The requirements set down by elite management became the engineering criteria for an efficient ground transportation system that would be adopted throughout the Maya world.
Maya engineers approached the challenge by focusing their creativity on the use of proven technical innovations to develop solutions for an all-weather highway. Their solution was one that would support a variety of two-way traffic and was constructible in a variety of environmental conditions, including jungle terrain, savannahs, and marshlands, using locally available materials. To develop the optimal design for a multi-functional, all-weather roadway, Maya engineers applied their proven technology, materials of construction, and engineering skills to develop the innovative prototype. They combined design and construction materials, including structural engineering, linear surveying, cast-in-place concrete, composite masonry and concrete systems, and construction management.
The design methodology for implementation of the engineered routes included a variable criterion that enabled construction of the roads in diverse terrains. The specifications allowed the use of local materials available along the route. The basic geometric profile of the sacbe required a 10-meter-wide, paved, concrete surface elevated a minimum of 1 meter above the ground surface by stone sidewalls and a cast-in-place concrete base. The smooth, white, concrete pavement of the road enabled a solid non-slip footing for travelers while resisting the growth of invasive jungle vegetation. To maintain a dry pavement, the surface of the concrete paving was shaped with a convex crown to facilitate the drainage of storm water from the road surface. The sidewalls elevated the roadway above the jungle floor to prevent flooding during the rainy season and deterred jungle growth. Maya engineers relied on the elevated surface of their roads to keep their pavement clear of mud, storm water, and the attack of the encroaching jungle. The geometry, construction details, and composition of the typical sacbe is shown in Figure 9-1 and Figure 9-2.
The Lost Secrets of Maya Technology Page 20
