Archaeologists uncover largest ancient dam built by Maya in Central America

Jul 16, 2012
This image shows excavation of the dam identified by the UC-led team. A collapsed sluice gate is outlined in red. Credit: University of Cincinnati researchers

Recent excavations, sediment coring and mapping by a multi-university team led by the University of Cincinnati at the pre-Columbian city of Tikal, a paramount urban center of the ancient Maya, have identified new landscaping and engineering feats, including the largest ancient dam built by the Maya of Central America.

That – constructed from cut stone, rubble and earth – stretched more than 260 feet in length, stood about 33 feet high and held about 20 million gallons of in a man-made reservoir.

These findings on ancient Maya water and land-use systems at Tikal, located in northern Guatemala, are scheduled to appear this week in the Proceedings of the National Academy of Sciences (PNAS) in an article titled "Water and Sustainable Land Use at the Ancient Tropical City of Tikal, Guatemala." The research sheds new light on how the Maya conserved and used their natural resources to support a populous, highly complex society for over 1,500 years despite environmental challenges, including periodic drought.

The paper is authored by Vernon Scarborough, UC professor of anthropology; Nicholas Dunning, UC professor of geography; archaeologist Kenneth Tankersley, UC assistant professor of anthropology; Christopher Carr, UC doctoral student in geography; Eric Weaver, UC doctoral student in geography; Liwy Grazioso of the Universidad de San Carlos de Guatemala; Brian Lane, former UC master's student in anthropology now pursuing doctoral studies at the University of Hawaii; John Jones, associate professor of anthropology, Washington State University; Palma Buttles, technical staff senior member, SEI Carnegie Mellon University; Fred Valdez, professor of anthropology, University of Texas-Austin; and David Lentz, UC professor of biology.

Starting in 2009, the UC team was the first North American group permitted to work at the Tikal site core in more than 40 years.

These are veneer stones of the dam identified by the UC researchers. What was once thought to be a sluice is outlined in red and is now filled with slump-down debris. Credit: University of Cincinnati researchers

Detailed in the latest findings by the UC-led efforts are:

  • The largest ancient dam built by the ancient Maya of Central America
  • Discussion on how reservoir waters were likely released
  • Details on the construction of a cofferdam needed by the Maya to dredge one of the largest reservoirs at Tikal
  • The presence of ancient springs linked to the initial colonization of Tikal
  • Use of sand filtration to cleanse water entering reservoirs
  • A "switching station" that accommodated seasonal filling and release of water
  • Finding of the deepest, rock-cut canal segment in the Maya lowlands
According to UC's Scarborough, "The overall goal of the UC research is to better understand how the ancient Maya supported a population at Tikal of perhaps 60,000 to 80,000 inhabitants and an estimated population of five million in the overall Maya lowlands by AD 700."

He added, "That is a much higher number than is supported by the current environment. So, they managed to sustain a populous, highly complex society for well over 1,500 years in a tropical ecology. Their resource needs were great, but they used only stone-age tools and technology to develop a sophisticated, long-lasting management system in order to thrive."

Water collection and storage were critical in the environment where rainfall is seasonal and extended droughts not uncommon. And so, the Maya carefully integrated the built environment – expansive plazas, roadways, buildings and canals – into a water-collection and management system. At Tikal, they collected literally all the water that fell onto these paved and/or plastered surfaces and sluiced it into man-made reservoirs. For instance, the city's plastered plaza and courtyard surfaces and canals were canted in order to direct and retain rainwater runoff into these tanks.

In fact, by the Classic Period (AD 250-800), the dam (called the Palace Dam) identified by the UC-led team was constructed to contain the waters that were now directed from the many sealed plaster surfaces in the central precinct. It was this dam on which the team focused its latest work, completed in 2010. This gravity dam presents the largest hydraulic architectural feature known in the Maya area. In terms of greater Mesoamerica, it is second in size only to the huge Purron Dam built in Mexico's Tehuacan Valley sometime between AD 250-400.

Said Scarborough, "We also termed the Palace Dam at Tikal the Causeway Dam, as the top of the structure served as a roadway linking one part of the city to another. For a long time, it was considered primarily a causeway, one that tourists coming to the site still use today. However, our research now shows that it did double duty and was used as an important reservoir dam as well as a causeway."

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. Credit: University of Cincinnati researchers

Another discovery by the UC-led team: To help purify water as it sluiced into the reservoir tanks via catchment runoff and canals, the Maya employed deliberately positioned "sand boxes" that served to filter the water as it entered into the reservoirs. "These filtration beds consisted of quartz sand, which is not naturally found in the greater Tikal area. The Maya of Tikal traveled at least 20 miles (about 30 kilometers) to obtain the quartz sand to create their water filters. It was a fairly laborious transportation effort. That speaks to the value they placed on water and water management," said UC's Nicholas Dunning.

According to UC's Ken Tankersley, "It's likely that the overall system of reservoirs and early water-diversion features, which were highly adaptable and resilient over a long stretch, helped Tikal and some other centers survive periodic droughts when many other settlement sites had to be abandoned due to lack of rainfall."

UC paleoethnobotanist David Lentz explained that the sophisticated water management practiced by the ancient Maya impacted the availability of food, fuel, medicinal plants and other necessities. He said, "Water management by the Maya included irrigation, which directly impacted how many people could be fed and overall population growth. Accordingly, it is essential to understand the array of canals and reservoirs at Tikal, which conserved water during the annual dry season and controlled floodwaters during the rainy months. These practices allowed the Tikal Maya to sustain relatively high population densities for several centuries. As it evolved, this system of reservoirs was largely dependent on rainfall for recharging. With the onset of the 9th century droughts however, water supplies dwindled, causing the resource base and social fabric of the Tikal Maya to come under considerable stress. These developments may well have contributed to the abandonment of the city."

Of significance to Scarborough and the entire team are the potential lessons that can be gleaned from identifying a water system like that at ancient Tikal. Said Scarborough, "Water management in the ancient context can be dismissed as less relevant to our current water crisis because of its lack of technological sophistication. Nevertheless, in many areas of the world today, the energy requirements for even simple pumping and filtering devices – to say nothing about replacement-part acquisition – challenges access to potable sources. Tropical settings can be especially difficult regions because of high infectious disease loads borne by unfiltered water schemes. The , however, developed a clever rainwater catchment and delivery system based on elevated, seasonally charged reservoirs positioned in immediate proximity to the grand pavements and pyramidal architecture of their urban cores. Allocation and potability were developmental concerns from the outset of colonization. Perhaps the past can fundamentally inform the present, if we, too, can be clever."

Explore further: Everglades trail surveyed for cultural artifacts

More information: “Water and sustainable land use at the ancient tropical city of Tikal, Guatemala,” by Vernon Scarborough et al. PNAS, 2012.

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User comments : 16

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NotParker
3 / 5 (8) Jul 16, 2012
""Water management in the ancient context can be dismissed as less relevant to our current water crisis because of its lack of technological sophistication."

Ha!!!

At least the Mayans were smart enough to build damns!

Modern greenies want to live in dry regions and picket anyone even thinking of building a damn to save water for natural drought cycles.
TheGhostofOtto1923
3.7 / 5 (19) Jul 16, 2012
Dams are not sustainable.
http://blog.green...rmanent/

-Perhaps mayans learned this the hard way...

"These developments may well have contributed to the abandonment of the city."

Nebucchadnezzar tried to rescue the euphrates valley by removing the top few feet of soil, which had become saltified from irrigation. He had to abandon the effort.
NotParker
2.3 / 5 (3) Jul 16, 2012
9th century drought was the development that contributed to abandonment.

Possibly this was the beginning of the MWP. Massive droughts do occur without SUV's.

Until that happened: "These practices allowed the Tikal Maya to sustain relatively high population densities for several centuries."
flyscan
4.7 / 5 (3) Jul 16, 2012
Dams are not sustainable.


"They collected literally all the water that fell onto these paved and/or plastered surfaces" This is not a dam built in a high silt area for electrical generation. Dams built in the Tikal Maya fashion are sustainable! Several centuries is pretty dam impressive, we're only up to our 3rd century since the industrial revolution.

The lesson is not "BUILD MOR DAMZZZ" but to apply intelligent design to our cities so that they are able to capture all the water that falls on them. We face the additional challenge of filtering car tire residue on the roads but it's nothing human ingenuity cannot solve.
NotParker
3.7 / 5 (3) Jul 16, 2012
capture all the water that falls on them


Where would you store that water when it doesn't rain ... for days or months?

The catchment area of the Grand Coulee Dam is 74,100 sq miles and it can hold 12 cubic km of water.

Torbjorn_Larsson_OM
5 / 5 (2) Jul 17, 2012
"Dams are not sustainable."

Well, this is the observation that rejects that unsupported claim. I also note that it was based on the idea that "dams can become silted up and the structures deteriorate. And from the point of view of migratory fish species and flooded forests, theres nothing sustainable about a dam."

Neither of those effects were present for these dams, with the possible exception of blocking fish. The article describes how the use of cofferdams enabled dredging and how the dams stood for many centuries. There were no flooding, since the city was populated.
Torbjorn_Larsson_OM
5 / 5 (2) Jul 17, 2012
[cont.] And I find the idea that it prevented fish migration unlikely. These were dams integrated with a city, we can as well blame urbanization which is the most resource efficient form of society known.

Even so, the position of Tikal made it unlikely. It was purposefully positioned a ways up due to earlier mismanagement of land, razing the forests made the earliest occupations unlivable - soil and wood poor, and flooding & disease rich.

The early agrarian communities were observably much more careless about nature and wasteful than we are. Of course they needed about 10 times as much land than todays efficient mechanized, fertilized and gene selected agrarian practices. Turns out, according to recent research for baselining AGW, they took all the continental forests down. (With the possible exception of large parts of the Amazon, but the evidence against is new and arguable.)

The Mayans learned from that.
Torbjorn_Larsson_OM
5 / 5 (1) Jul 17, 2012
An order of magnitude more land per capita that is.

It is interesting, and of course promising, that regrowth of dense forests must have been possible between the initial sacking so many millenniums ago and later attrition.
TheGhostofOtto1923
3.9 / 5 (15) Jul 17, 2012
"They collected literally all the water that fell onto these paved and/or plastered surfaces" This is not a dam built in a high silt area for electrical generation. Dams built in the Tikal Maya fashion are sustainable! Several centuries is pretty dam impressive, we're only up to our 3rd century since the industrial revolution.
There is not a lot of info here but it appears they collected all city runoff, which includes all that cities normally produce ie sewage, debris, rotting garbage, leaves, etc similar to medieval London. NYC does the same thing today with a combined storm and sewer system.

No wonder they filtered it. Crud removal would have been even more critical than normal siltation. And it does not say for how long this system functioned, only the length of time the civilization existed.

History records many massive public works projects right before social collapse, in desperate but futile attempts to defray the effects of overpopulation.
NotParker
5 / 5 (3) Jul 17, 2012

History records many massive public works projects right before social collapse, in desperate but futile attempts to defray the effects of overpopulation.


Actually, when a country like the USA stopped building big dams and the Chinese kept on building them, it was a sign of the end of the USA.

Greenies hate dams.
TheGhostofOtto1923
3.9 / 5 (15) Jul 17, 2012

History records many massive public works projects right before social collapse, in desperate but futile attempts to defray the effects of overpopulation.


Actually, when a country like the USA stopped building big dams and the Chinese kept on building them, it was a sign of the end of the USA.

Greenies hate dams.
Chinese dam fail
http://www.youtub...KSBaqGQs
http://en.wikiped...qiao_Dam
http://www.tobacc...ary.html
http://online.wsj...475.html

-Maybe they get better with practice? China has a history of imitating western tech which kills millions.

"The Great Leap ended in catastrophe, resulting in tens of millions of excess deaths. Estimates of the death toll range from 18 million to 45 million..."
http://en.wikiped..._Forward

-Although pop reduction was probably the intended result.
TheGhostofOtto1923
3.8 / 5 (16) Jul 17, 2012
"The Banqiao Reservoir DamChina. Its failure in 1975 caused more casualties than any other dam failure in history. It was subsequently rebuilt.
The Banqiao dam and Shimantan Reservoir Dam are among 62 dams in Zhumadian Prefecture of China's Henan Province that failed catastrophically or were intentionally destroyed in 1975 during Typhoon Nina.
The dam failures killed an estimated 171,000 people; 11 million people lost their homes. It also caused the sudden loss of 18 GW of power[citation needed], the equivalent of roughly 9 very large modern coal-fired power stations or about 20 nuclear reactors, equalling about 1/3 the peak demand on the UK National Grid."

-Can you perhaps find any more references that can be worse examples than chinese dams? Well you could try.
http://en.wikiped..._removal
NotParker
5 / 5 (3) Jul 17, 2012
"The super-typhoon resulted in 64.2 in of rain, 33 in of which fell in a six hour span.

These rains led to the collapse of the Banqiao Dam, which received 1-in-2000-year flood conditions"

Some things you just can't plan for.

It doesn't mean you give up.
TheGhostofOtto1923
3.9 / 5 (15) Jul 17, 2012
These rains led to the collapse of the Banqiao Dam, which received 1-in-2000-year flood conditions"
"...among 62 [OTHER] dams in Zhumadian Prefecture of China's Henan Province that failed catastrophically or were intentionally destroyed in 1975 during Typhoon Nina."
It doesn't mean you give up.
Hey did you see that really cool chinese bridge collapse?
http://english.si...678.html

"At least 22 people were killed today when a newly-built bridge collapsed in central China, raising fresh concerns about safety standards amid a nationwide construction boom."

-They made it out of stone, just like in the old days.
NotParker
5 / 5 (3) Jul 17, 2012
among 62 [OTHER] dams in Zhumadian Prefecture of China's Henan Province that failed catastrophically or were intentionally destroyed in 1975 during Typhoon Nina."


The wikipedia article certainly implied those other dams failed because the big one failed leading to a large amount of water going downstream where those other dams were.

TheGhostofOtto1923
3.9 / 5 (15) Jul 17, 2012
The wikipedia article certainly implied those other dams failed because the big one failed leading to a large amount of water going downstream where those other dams were.
Well not really. It did say there was a LOT of water throughout the region, and that flood planning and control was abysmal.

"After the disaster of the Banqiao dam failure, the Chinese government became very focused on surveillance, repair, and consolidation of reservoir dams. China has 87,000 reservoirs across the country; most of which were built in the 1950s-1970s using low construction standards. Most of these reservoirs are in serious disrepair, posing challenges to the prevention and control of flood-triggered geological disasters in areas with a population of 130 million or more. China's medium and small rivers are considered to be the Achilles' heel in the country's river control systems."