Water Management: Reservoirs and Chinampas

The southern Maya lowlands sit on a porous limestone shelf that absorbs surface water almost as fast as it falls. Rivers are few, soils are thin, and the dry season is severe. The ancient Maya responded to these constraints with an engineering repertoire that ranged from household-scale cisterns to citywide systems of terraces, canals, and raised fields. The full range of Maya food production is treated in Maya Agriculture, Food, and Cuisine; this page focuses on the hydraulic works that complemented the milpa described in The Milpa: Slash-and-Burn Farming and the three-sister polyculture of Maize, Beans, and Squash: The Three Sisters. The climate challenge that drove this engineering is also discussed in How Did the Maya Farm in Dense Rainforest? and in the wider context of History of the Maya Civilization.

The story of Maya water management is closely tied to the political history of the major cities, summarized in Major Maya Cities and Archaeological Sites and in Tikal: Heart of the Classic Maya World.

The challenge of the karst

The Yucatán Peninsula is a flat, low-lying platform of Cretaceous limestone, broken by a few ranges of low hills (the Puuc, the Chenes, the Sierra de San Carlos) and by the volcanic highlands of the Pacific piedmont. Rainfall in the central lowlands averages 1,200 to 1,800 millimeters per year, almost all of it falling between May and December. The dry season lasts four to five months. The result is a hydrology in which there are essentially no surface streams in the central and northern lowlands: the water sinks into the limestone, flows through cave systems, and emerges at cenotes (natural sinkholes), aguadas (seasonally flooded sinkholes), and the small rivers of the southern and eastern margins.

A community in this landscape had to do two things: capture rainwater where it fell, and access groundwater when surface water failed. The Maya did both, with a series of complementary technologies.

Aguadas

The simplest and oldest form of Maya water storage is the aguada, a natural sinkhole in the limestone. Aguadas vary in size from a few hundred to several thousand square meters, with depths of a few meters to over twenty. Maya farmers modified aguadas in three principal ways: by deepening the basin, by plastering the floor and walls with lime plaster to reduce seepage, and by building a low earth dam across the lowest outlet to retain water in the dry season.

Aguadas were community resources. A single aguada typically served a small hamlet or a cluster of milpas, and it was often associated with a small shrine. The archaeologist Norman Hammond’s survey of the Cuello site in northern Belize, for example, identified a sequence of Plazuela-era and later aguadas that anchored the settlement from the Early Formative through the Late Classic. Larger aguadas, such as the Aguada Lamina in Quintana Roo, served multiple communities and supplied ceremonial and household water to thousands of people.

Chultuns

A chultun is a bottle-shaped underground cistern, cut into the soft limestone bedrock and sealed with lime plaster. The chultun has a narrow opening at the surface, expanding into a domed or bottle-shaped chamber that may be 2 to 5 meters deep and 1 to 3 meters in diameter. A chultun at a typical Classic-period household could hold several cubic meters of water, enough to supply a family through the dry season.

Chultuns are ubiquitous in the central and northern Maya lowlands. The survey of Becán in Campeche identified chultuns associated with almost every house platform; the chultuns were typically cut into the bedrock just below the house floor, accessed by a small stone-lined opening, and used both for water and for the storage of maize and other dry goods. The chultun is a simple, robust technology, and it remained in use into the 20th century.

Plastered reservoirs

For larger communities, the principal water storage was a plastered reservoir, sometimes called ch’en in colonial and modern Maya terminology. The basic design is a rectangular basin cut into the limestone, lined with a thick layer of lime plaster, with a plastered slope or staircase leading down to the water. The best-studied example is the Tikal reservoir complex at the site of Tikal: Heart of the Classic Maya World.

The Tikal reservoir complex consists of a series of large plastered basins built into the bajo (seasonal swamp) south and east of the city center. The two largest — labeled by the archaeologists as Corriental and Temple reservoirs — together held an estimated 90,000 to 400,000 cubic meters of water, depending on assumptions about the size of the original basins and the catchment. The reservoirs were fed by a system of dams and ditches, were designed to be drained and cleaned periodically, and were connected to the urban core by causeways. They are the largest public water works in the central Maya lowlands, and they sustained the population of Tikal during the dry season.

A similar but smaller system is known at Caracol in western Belize, where plastered reservoirs are scattered through the urban core and the agricultural terraces. The site of Calakmul in the Calakmul Biosphere Reserve preserves another Late Classic system; the site of Naranjo, Quiriguá, and Yaxha all have reported reservoirs of varying size. The wider distribution of the technology is mapped in the Site of Copan and Site of Palenque studies, where plastered basins of the same design are found in the central precincts.

Edzná and the canal-rim cities

The most extensive Maya hydraulic complex is at Edzná, in the karst plain of Campeche. The site is surrounded by a system of canals, causeways, and basins that radiate from the civic center and integrate the urban core with the agricultural hinterland. The principal canal — sometimes called the canal principal — runs about 6 kilometers and is between 2 and 5 meters deep and 10 to 20 meters wide. Lateral canals branch from the main canal to the surrounding fields, and a series of basins and causeways line the system.

Edzná’s canal system has been interpreted variously as a means of water storage, of irrigation, of transportation, of fish farming, and of field drainage. The most likely interpretation is that it was multi-functional. During the wet season, the canals drained excess water from the surrounding fields; during the dry season, they retained water for irrigation; and at all times they served as fish habitat, as transport corridors, and as sources of water for household and ritual use. The canal system is similar in concept to the better-known Aztec chinampas of the Basin of Mexico, although the Edzná version is larger in scale and built in a different ecological setting.

Other canal-rim sites of the central lowlands include the Río Bec and Chenes regions, the Puuc sites of Sayil and Labná, and the northern Yucatán sites of Uxmal and Chichen Itza. At Uxmal, the Pyramid of the Magician is associated with a network of chultuns and a small reservoir. At Chichen Itza, the Sacbe 1 and the Cenote Sagrado anchor a complex system of causeways, plazas, and wells.

The Belize wetlands and the raised fields

The largest single example of intensive Maya wetland agriculture is the raised-field complex of the coastal wetlands of northern Belize, especially in the Hondo, New, and Belize river basins. The basic unit is a rectangular raised field, 5 to 20 meters wide and 20 to 100 meters long, separated by canals 1 to 3 meters deep. The fields are built up from the excavated canal mud, and they form a grid that breaks the wetland into a network of artificial islands.

The raised fields were intensively used in the Late Classic and Postclassic periods. Pollen and phytolith analysis of buried field surfaces at Pulltrouser Swamp, Colhá, and the Saturday Creek area shows that the principal crops were maize, manioc (Manihot esculenta), and a range of root crops adapted to wet conditions. The canals, in addition to draining and supplying the fields, were used to grow aquatic crops — Ix (water lily) tubers, water spinach (Ipomoea aquatica), and other aquatic plants — and to produce fish, turtles, and shellfish.

The size of the raised-field complex is remarkable. Detailed survey of the Saturday Creek and Northern River Lagoon areas, combined with the LIDAR mapping that has revolutionized Maya archaeology, has documented raised fields over more than 100 square kilometers, and the total is likely larger. The fields were connected to the urban centers of Cerros, Colhá, Lamanai, and Punta Gorda by a network of canals and the broader network of canoeable rivers.

The Maya raised field is functionally similar to the Aztec chinampa of the Basin of Mexico, although the ecological setting is different. The Aztec chinampa is a small rectangular field built up in a shallow lake, with a deep canal on one or more sides and a willow or ahuejote tree at the corner. The Maya raised field is a larger, more canal-bound structure in a seasonal wetland. The technology is sometimes called Maya chinampa in the literature, but the more accurate term is raised field or plataforma.

Terraces at Caracol and beyond

Where the topography allowed, the Maya built agricultural terraces — long, level platforms cut into a hillside, supported by dry-stone retaining walls. The terraces slowed runoff, captured soil, and created flat, deep, moisture-retentive planting surfaces. The best-known example is at Caracol in the Chiquibul Forest of western Belize, where archaeological survey combined with LIDAR has mapped more than 50 square kilometers of terraced slopes, the largest agricultural terrace system in the Maya world.

The Caracol terraces have been studied in detail by the archaeologist Diane and Arlen Chase and their colleagues. The terraces at Caracol are associated with the Late Classic expansion of the city from c. 600 to 800 CE. The system, in conjunction with the city’s reservoirs and the surrounding forest gardens, is estimated to have supported a population of 100,000 or more, in an environment that has been described as marginal at best for agriculture. The terraces also reduced erosion and runoff into the karst, with the result that downstream communities continued to have clean, perennial water in springs and aguadas.

Smaller terracing is reported at the highland sites of Copan, Kaminaljuyú, and the Sierra de los Cuchumatanes, and on the slopes of the Maya Mountains. The technology of the Maya terrace is related to the highland Mexican and Andean terraces, but the Maya version is distinguished by the use of uncut stone, by the dry-stone retaining walls, and by the absence of elaborate water-channel features.

Forest gardens and the pet kot

The Maya also practiced a form of forest gardening that combined the natural forest with selectively spared food trees. The Yukatek Maya term for this is pet kot, “circular field,” referring to a small plot of forest around a household or shrine, in which the canopy trees are managed and useful species are favored. The K’iche’ and Tzeltal Maya use terms like guamil and acahual for similar managed fallows.

The forest garden is a low-input, high-diversity system. The principal species include:

Ramón (Brosimum alicastrum) — a large, evergreen tree of the Moraceae, with a sweet seed eaten as a nut and ground into flour. Ramón is one of the most important forest-garden trees, with a yield that can supplement the maize harvest in lean years.
Chicle (Manilkara zapota) — the source of chewing gum, still tapped in the Petén.
Mamey (Pouteria sapota) — a large fruit tree with sweet, salmon-colored flesh.
Sapodilla (Manilkara zapota) — a relative of chicle, with a sweet, brown, granular fruit.
Allspice (Pimenta dioica) — the source of the pimienta gorda used in Maya cooking.
Cacao (Theobroma cacao) — the prestige tree, treated in Cocoa, Salt, and Maya Trade Goods.
Avocado (Persea americana) — domesticated in Mesoamerica and widely grown.

The forest garden is a multi-story system, with a canopy of large trees, a sub-canopy of fruit and spice trees, and a ground layer of root crops and herbs. It is one of the most productive agroforestry systems in the world, and it is closely related to the Amazonian terra preta soils and to the modern Indigenous agroforestry movements in the Maya lowlands. The general principles are discussed in How Did the Maya Farm in Dense Rainforest?.

The political economy of water

The engineering of water was not just a matter of technology. The reservoirs, the terraces, the canals, and the raised fields all required substantial labor, and the political organization that could mobilize that labor is part of the story of the Major Maya Cities and Archaeological Sites.

At Tikal, the reservoir complex was associated with the kings of the Late Classic and was probably used in part to support a redistributive feasting economy, with the ruler as the central purveyor of water and food. At Caracol, the terracing is associated with the Late Classic expansion under the dynasty of Lord K’an II, and the agriculture is thought to have been the economic basis for the city’s power. At Edzná, the canal system may be even older, perhaps Early Classic or Late Formative, and it has been interpreted as a state-sponsored project of public water control.

The decline of these systems is part of the story of the Causes of the Classic Maya Collapse. When the southern lowland cities were depopulated in the ninth century, the reservoirs silted up, the canals filled in, the terraces eroded, and the wetland fields returned to forest. The recovery of the same systems in the Postclassic, especially in the Puuc and northern Yucatán, suggests that the engineering knowledge was retained and adapted.

Conclusion

The Maya were among the most skilled hydraulic engineers of the pre-Columbian Americas. The agudas, the chultuns, the reservoirs, the terraces, the canals, and the raised fields were not isolated technologies but a single, integrated system of water and soil management that sustained the agriculture of one of the densest pre-industrial populations of the world. The system combined the milpa described in The Milpa: Slash-and-Burn Farming, the three-sister polyculture of Maize, Beans, and Squash: The Three Sisters, and the engineering of the major cities, as described in Maya Agriculture, Food, and Cuisine and Major Maya Cities and Archaeological Sites.

Sources

Fedick, S. L., ed. (1996). The Managed Mosaic: Ancient Maya Agriculture and Resource Use. University of Utah Press. — link
Beach, T. et al. (2017). Ancient Maya wetland fields in Belize: Measuring, modelling and managing ancient tropical environments. Journal of Archaeological Science: Reports 13, 476–487. — link
Wilkinson, T. J. et al. (2006). Classic Maya Water Management at Tikal, Guatemala. Journal of Archaeological Science 33 (10), 1362–1384. — link
Re Cruz, A. (1996). The Two Milpas of Chan Kom: A Study of Seasonal and Year-round Labor Force Organization in a Mayan Community. University of Texas Press. — link
Cancian, F. (1972). Change and Uncertainty in a Peasant Economy: The Maya Corn Farmers of Zinacantán. Stanford University Press. — link