Archaeologists have discovered the oldest pressurized water system in the New World, an aqueduct-tunnel system in the southern Mexico site of Palenque that probably powered a fountain or a waste water system.
Such pressurized water systems appeared in the Old World at least as long ago as 1400 BC: The remains of such a system have been found in a Minoan palace in Crete. But the apparent lack of similar remains in the Americas led most archaeologists to assume that they did not appear here until they were brought by the Spanish in the 16th century.
The new find in the Maya city, which was first occupied about AD 100 and abandoned 700 years later, indicates that at least one American culture developed such systems independently. Pressurized water systems are necessary for fountains, among other uses. If water is not pressurized, it simply bubbles out of the ground rather than spraying dramatically upward in a display.
The aqueduct-tunnel structure was discovered in 1998 by then-graduate student Kirk D. French when he was part of a team mapping the city's ruins, but he did not immediately recognize its significance. It was only when French, now at Pennsylvania State University, consulted hydrologist Christopher J. Duffy of Penn State and the pair returned to the site that they appreciated the structure's import, French said.
The site is crossed by a number of streams, and the Maya — who were not considered great structural engineers but who developed excellent systems for controlling water flow and for storing water in reservoirs for the dry season — built many underground aqueducts at Palenque to channel the water and control flooding during the rainy season.
The aqueduct in question, however, is unique, the researchers reported in the current issue of the Journal of Archaeological Science. The cross-section is about 10 square feet for most of its length, but a sharp constriction near its end reduces the size to about half a square foot.
"It's like putting your thumb on the end of a water hose," French said. "The smaller you make the hole, the farther the water goes."
Duffy calculated that the pressure increase caused by the constriction was sufficient to force water 20 feet into the air.
There are no remains left at the end of the aqueduct, so the pair do not know for sure what the water pressure was used for. But a fountain is probably the best bet, French said.
"I really think the elite were using this as a kind of showing off, a display of wealth and power to say 'We can do this, we can make water rise right out of the ground.'"