Ancient Hydraulic System at Tikal: Uncovering Maya Water Control

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Water Control Systems at Tikal

Great Plaza at Tikal, Peten, Guatemala
Great Plaza at Tikal, Peten, Guatemala. Takeshi Inomata (c) 2006

The Maya Capital of Tikal, with a population estimated between 45,000-65,000 in its heyday between 682-800 AD, did not have access to a natural source of freshwater, such as a major perennial stream or lake. Rain in the rainforest of Guatemala's Petén falls primarily in the wet season. More than 80% of the annual rain falls between May and November; and all of that quickly slips through the local porous karst topography away from the surface. Today, potable water must be trucked in for the use of the residents at the nearby town of Zocotzal, including the staff of Tikal National Park. And yet, the city state grew and flourished for over 1,500 years. How did they do that?

In the 21st century, archaeologists discovered the remains of a complex hydraulic system of canals, dams, reservoirs and filtration systems at Tikal. The Maya hydraulic system at Tikal begun as early as the Middle Preclassic period, in the 6th century BC, and it was refined and reconfigured many times up until 900 AD, when it abruptly failed. This research has detailed the elements of the system, and attempted to explain why what had been a sustainable urban environment so disastrously ended. This photo essay presents some of the findings to date.

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Discovery of the Hydraulic System at Tikal

Map of the Urban Center of Tikal with Reservoirs Drawn in Blue
Map of the Urban Center of Tikal with Reservoirs Drawn in Blue. No. 7 on the map is the central acropolis at Tikal, the three blue blobs directly south of 7 are, from west to east, the Temple, Palace and Hidden reservoirs. Elelicht

Many of the elements of the hydraulic system at Tikal are enormous, and they were early recognized as Maya-built earthworks. Identification of segments of a large ditch and embankment combination which appeared to surround the central core of Tikal first occurred among archaeological circles during the mapping of Tikal in the 1960s. Archaeologists Dennis Puleston and Donald W. Callender interpreted it as a defensive barrier and boundary. Beecause there were some discrepancies Puleston and Callender were explicitly tentative in their identification, but the notion of a defensive barrier surrounding Tikal became established for some 40 years.

But in the first decade of the 21st century, a University of Pennsylvania team led by David Webster and his students reevaluated the earthwork, and discovered that although the northern and western segments do appear to have a defensive function, the remainder of the earthwork segments mapped by Puleston and Callendar were not engineered to be defensive functions. They hypothesized (described in Silverstein et al. 2009) that there was a previously undiscovered, immense water control system at Tikal. Later studies by the University of Cincinnati have added to this study, revealing that Tikal's rulers constructed a massive water system, with reservoirs, dams, canals, causeways, filtration systems and ditches to control access to water during the seasonal climate variations.

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Reservoirs at Tikal

Maya Reservoir at Tikal
An ancient Mayan reservoir at Tikal is unearthed, providing new insights into how the ancient Maya built for water management. University of Cincinnati

The main elements of the Maya water control system were reservoirs, deep excavated tanks of water which collected the wet season precipitation running off expansive plaster surfaces on plazas and courtyards, which had been deliberately sloped to do just that. There are six large reservoirs mapped in the 9 square kilometer (2,200 acres, or about 3.5 square miles) center of Tikal. Those reservoirs had been excavated around four separate existing arroyos: in the early studies of the site these reservoirs were thought to be stone quarries, and they probably were as well.

Three prominent arroyos cut west to east through the central Tikal zone: the arroyo south of the main Palace was the most significantly altered. Three reservoirs were cut in a chain into this southernmost arroyo, called the Temple, Palace and Hidden reservoirs: others such as the Perdido and Corriental were located at swamp margins and still others (such as Tikal, Terminos, Inscriptions, Madira) were scattered around the city.

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The Temple Reservoir

Central Acropolis at Tikal
Central Acropolis at Tikal. TausP.

The Temple Reservoir at Tikal was the highest in elevation and closest to the plaza of the three main reservoirs, but it was also the smallest tank, with a volume of approximately 27,130 cubic meters (over 7 million US gallons). The tank was roughly circular and about 90 meters (300 feet) across and about 8 meters (26 ft) deep. Its location surrounded by the city's most impressive structures suggested to Scarborough et al. that it had a ritual significance, but there is no doubt that the rainwater runoff from the huge structure was also important.

Expansion was completed by creating silting tanks, then quarrying the deeper main body and lining it with clay. Berms were partly contoured bedrock and partly consolidated fill. The Temple Reservoir was first constructed by at least 521-216 cal BC (Preclassic) and extensively remodeled during the Classic Period.

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Palace Dam and Reservoir

Sluice Gate in the Palace Dam at Tikal
This image shows excavation of the Palace dam at Tikal identified by the University of Cincinnati-led team. A collapsed sluice gate is outlined in red. University of Cincinnati researchers

To the east of the Temple reservoir was the Temple causeway which separated the Temple reservoir from the Palace reservoir, and it acts as a coffer dam. The Palace Reservoir was the largest of the three central tanks, estimated to have contained a water volume of some 74,361 m3 (16,800 gal). It was about 280 m (920 ft) long and up to 60 m (200 ft) wide and about 5 m (16 ft) deep. It was created by a dam at the eastern end, separating it from the Hidden Reservoir. The basal channel for the Palace Reservoir was only about 1 m (3.3 ft) deep, but the adjacent limestone bench had been carved out and widened.

The Palace Dam creating the Palace Reservoir was constructed by the Late Preclassic Period, with sloping basal dimensions of 80x60m by 10 m high (260x200x30 ft), and it was likely first built somewhere between 358-55 cal BC. It is the largest prehistoric hydraulic feature in the Maya area, and only the second largest in all of prehispanic Mesoamerica (the largest is the Late Preclassic/Early Classic Purrón Dam in the Tehuacan Valley). The dam was built of part of the original escarpment, enhanced with cut-stone and rubble and earthen construction sealed with cut veneer stone. Sluice gates were created by vertically stacked openings, although they are poorly preserved today.

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The Corriental Reservoir and Canal

Maya Canal at Corriental Reservoir, Tikal, and Researcher Liwy Grazioso
This is a view of a Maya-built canal. Pictured is Guatemalan researcher Liwy Grazioso, who has participated in the work by a UC-led team. University of Cincinnati Research Team

The Corriental reservoir was one of four Maya water tanks located next to above seasonally inundated depressions or "bajos" within central Tikal. Corriental was one of the largest at Tikal, with an estimated capacity of 57,000m3 (1.5 million US gal) of water, and it was strategically positioned to collect most of the surface water runoff from the southeastern city. Corriental is surrounded by a 4-7 m (13-23 ft) high berm with two gates providing water entrance (ingresses) and one complex spillway (egress). A two-meter deep canal with a v-shaped channel directed catchment waters into the tank.

The tank itself was built during the Middle Preclassic (760-400 cal BC), and it was constructed with a filtration device to filter the runoff to create potable water. A seasonally adjusted switching station was created by the Late Preclassic, as was the canal: the Late Preclassic is associated with an intensified drought cycle. See Scarborough et al. 2012 for details.

Corriental was likely used as a public water source for drinking, cooking and probably also bathing. Tankersley et al. also discovered evidence for volcanic ash fall, suggesting periodic eruptions by volcanoes during the Preclassic, Classic and Postclassic periods, perhaps El Chichon, Tajamulco, Acatenango and/or Atitlan which were active between AD 600-800 and Cerro Quemado, about AD 800.

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The System's Effectiveness

Tikal Temple V
Tikal Temple V. Antti T. Nissinen

The Maya hydraulic system at Tikal as a whole was remarkably resilient and flexible: adjustments were made to diversion and filtration work properly and adjust for high water periods during the Classic period and low water periods during the Terminal Preclassic. Scholars suggest that it was established at the oneset of a Terminal Preclassic drying trend, that allowed Tikal to survive when other centers were abandoned.

The system worked for nearly 1500 years, until AD 900, when Tikal's central control simply could not supply all the water demands created by an enormous population and an extended drought. Evidence at Corriental indicates that it continued function into post-Maya collapse. But prior to that, the system was sustainable, preventing overexploitation of resources, as the Maya people adjusted and adapted it for over a thousand years.

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Further Reading on Water Control Systems at Tikal

Map of the Main Buildings at Tikal
Map of the Main Buildings at Tikal. Simon Burchell

Sources

This article is a part of the About.com guide to the Maya Culture, and it is one of several cases examined in our series on Ancient Water Control Systems.

  • See the main entry on Tikal for additional information.
  • This research is part of the Integrated History and future of People on Earth (IHOPE) initiative

Lentz D, Dunning NP, Scarborough V, Magee KS, Thompson KM, Weaver E, Carr C, Terry RE, Islebe G, Tankersley KB et al. 2014. Forests, fields, and the edge of sustainability at the ancient Maya city of Tikal. Proceedings of the National Academy of Sciences 111(52):18513-18518. doi: 10.1073/pnas.1408631111

Scarborough VL, Dunning NP, Tankersley KB, Carr C, Weaver E, Grazioso L, Lane B, Jones JG, Buttles P, Valdez F et al. 2012. Water and sustainable land use at the ancient tropical city of Tikal, Guatemala. Proceedings of the National Academy of Sciences 109(31):12408-12413. doi: 10.1073/pnas.1202881109

Silverstein JE, Webster D, Martinez H, and Soto A. 2009. Rethinking The Great Earthwork of Tikal: A Hydraulic Hypothesis for the Classic Maya Polity. Ancient Mesoamerica 20(01):45-58. doi: 10.1017/S0956536109000042

Tankersley KB, Scarborough VL, Dunning N, Huff W, Maynard B, and Gerke TL. 2011. Evidence for volcanic ash fall in the Maya Lowlands from a reservoir at Tikal, Guatemala. Journal of Archaeological Science 38(11):2925-2938. doi: 10.1016/j.jas.2011.05.025