Maya reservoirs could inform future water management
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The Classic Maya who lived in the tropical southern lowlands of Central America from around 250-900 A.D. relied on reservoirs to survive their five-month dry season and sporadic droughts.
But how did they keep their water clean?
The answer could hint at ways to improve water quality and availability under climate change.
A new paper in the journal PNAS argues that Classic Maya reservoirs functioned much like constructed wetlands, which emphasize ecological improvement and pollutant removal.
Based on archaeological evidence, pollen preserved in sediment cores and Maya iconography, the author describes how certain aquatic plants removed excess nutrients like nitrogen and phosphorus, which can promote algae growth.
Such wetlands also would have supported diverse zooplankton that prey on pathogens and bacteria.
Pollen records and royal iconography confirm the presence and importance of water lilies, which only grow in clean water.
Looking to the future, the author describes how cheap, low-tech and low-energy constructed wetlands could help fulfill a call by the fourth Intergovernmental Panel on Climate Change to expand rainwater harvesting.
More adaptable water management techniques could also help communities cope with the water quality and disease crises that often accompany droughts or floods.
The lush environs surrounding Maya cities would seem to indicate moisture aplenty. But much of the region’s water percolates through the soluble rocks that lie beneath the soil. This problem was exacerbated as tropical vegetation was removed more and more throughout the Late Classic period, around 600-800 A.D.
Not surprisingly, water became an object of reverence for the Maya, and providing clean water became a source of power and prestige for its rulers.
Every one of the hundreds of ancient Maya cities spread across southeastern Mexico, northern Guatemala, Belize and western Honduras has water management features, especially reservoirs.
Archaeologists have excavated gravity-fed reservoirs built as far back as 400 B.C. By 700 A.D., the Maya had incorporated dams, channels, switching stations and filtration systems.
So, Maya famers lived two lives: one in the country during the rainy season, and another one in the cities during the dry season, where they would perform labor in exchange for water.
