The ancient Maya culture of Central America is famous for its weird mathematics and accurate astronomy, its human sacrifice and ritualistic self-torture. But a group of archaeologists say the Maya should also be renowned for something more mundane: their municipal water works.
Buried in the steaming swamps of Guatemala, at the well-studied ruins of Tikal, the Maya left behind a ceremonial city of stone pyramids, palaces and plazas. Largely overlooked, until now, is a clever network of reservoirs and dams, stone-paved storm sewers and clay-lined drainage ditches that may have helped the Maya survive brutal bouts of seasonal drought.
Archaeologists say those waterworks may have placed essential resources under the control of a small political elite. The management of water, the researchers say, could have been crucial in the creation of the powerful and advanced Maya nation-state.
"You control the water and you control the economy. You control the water and you control the social systems. Water could have been an extremely important factor in the development of the Maya," said Vernon Scarborough, an anthropologist at the University of Cincinnati who published new research on the reservoirs of Tikal in the Feb. 8 issue of the journal Science.
The ability to manage water lies at the center of vigorous debate over the rise and fall of the Maya, who built one of the Western world's greatest civilizations. It mysteriously collapsed about 900 AD.
In much the same way that aggressive water managment drew large populations to the arid landscape of Los Angeles and Phoenix, the Maya elite may have constructed elaborate systems to collect and store rainwater to draw settlers to their ceremonial centers.
"Water could have been a powerful lure," Scarborough said. "It could have gathered together a large support population to serve the elite."
Some scholars now believe that not only was the manipulation of water, and all its attendent political machinations, crucial for the ascent of the Maya, but that a failure to maintain their water systems could have led to their downfall as well.
Just like present-day Californians, the Maya may have overextended their agriculture and city-building beyond their water capacities.
At their apex, the Maya occupied a nearly continuous territory covering southern Mexico, Guatemala and northern Belize. They constructed more than 40 substantial cities, and their population reached at least several million, if not more.
Though the Maya got plenty of rain most of the year, they were cursed by a long dry season and lack of both perennial rivers and year-round springs.
Their territory in the lowlands consisted of dense forest and bajo, a seasonal swamp that lies under water for part of the year. The underlying geology is limestone, as porous as Swiss cheese. The water table lies so deep it is beyond the reach of hand-dug wells. 'Very Sophisticated System of Collection'
Scarborough and his colleague, Gary Gallopin of the State University of New York at Buffalo, reexamined old site maps of Maya cities and discovered an interesting thing. The cities were dotted with rainwater reservoirs.
Indeed, structures at Tikal that were once thought to serve primarily as raised, ceremonial highways are now believed by Scarborough and Gallopin to be nothing less than elaborate berms to direct rainwater runoff into reservoirs. The entire city appears to be one big water catchment system.
The land in and around Tikal is divided into at least six large drainage areas that collected rainwater and directed the runoff into a dozen reservoirs. These reservoirs were not haphazard affairs, but show evidence they were actively worked, with earthen berms and stone tiling. In at least one case, there are what appear to be remnants of a floodgate.
The reservoirs of Tikal served three areas: the city's ceremonial center, the residential neighborhoods and the outlying agricultural lands, which adjoin an immense swamp, the Bajo de Sante Fe. The ceremonial center was almost entirely paved and was sloped to drain rainwater away from the plazas and into reservoirs.
"It was a very sophisticated collection system," said Peter D. Harrison, an adjunct professor at the University of New Mexico, who excavated the Palace Reservoir, which was lined with limestone blocks. The reservoir appears to have served first as a quarry for construction stones, but as the pit got deeper, it was eventually converted into a reservoir. Harrison said the tank was sealed at the bottom with mud. Steps lead down to the pool, which Harrison suspects was used for drinking, cooking, laundry and washing.
Outside the immediate city center, the larger reservoirs could have served to irrigate crops grown in the seasonally dried swamps.
Some scholars believe that the Maya were diligent farmers of the swamps. What they would have done was pile up the muck from the bajos and create raised gardens, which would have been surrounded by culverts and drainage ditches. The muck from the swamp and ditches would have been wonderfully fertile soil.
T. Patrick Culbert of the University of Arizona is a leading proponent of the idea that the Maya world was one big swamp garden. If the Maya were actively farming the swamps, which cover as much as half their land, they could have supported huge populations. If they were not farming the swamps, the Maya populations, and hence the complexity of the society, would have been reduced. A Tool of the Aristocracy
Based on his ideas about swamp farming, Culbert estimates that population densities could have reached "staggering" proportions -- as high 200 people per square kilometer, which would rival the most aggressively farmed area of rural China.
Such intense agriculture, coupled with centralized water management, would have required a high degree of social organization. Scarborough believes the use of water could have been one of several tools in the hands of the elite priests and aristocracy, who could have used the reservoirs as both a lure and a threat.
"The water system is a resource," Harrison said. "It provides a mechanism for centralization. It gathers the nobility in one place, a place to meet and a place to trade goods."
The reasons for the collapse of the Maya remain unknown. Some scholars argue the population outstripped resources. It is possible, too, that a failure to maintain their elaborate waterworks and raised gardens contributed to their downfall.
"What went wrong?" asks Culbert. "I don't know. I have a hunch it is a classic case of overpopulation and overexploitation of the environment. I think they had trouble supporting their whole system."