오늘의 가르침을 주는 마야의 물 체계

A rendering of the ancient Tikal settlement and its water collection and diversion system.

A little over 2,000 years ago, many of the Maya were on the move.

They abandoned the eroded and deforested low-lying land on the Yucatan peninsula – probably because of a bad drought – and headed to hillier elevations in what is now modern-day central Guatemala, according to Vernon L. Scarborough, an anthropologist at the University of Cincinnati. There they began to build Tikal, one of the largest and most successful Mayan settlements.

University of CincinnatiThe Temple of the Great Jaguar at Tikal.

A settlement, though, needs resources. When the Maya moved, they needed to devise a complex water collection and usage system that would sustain Tikal for nearly a millennium. This system is described by Dr. Scarborough and his colleagues in a new paper published online on Monday in the Proceedings of the National Academy of Sciences.

While scientists have learned much about the Maya by mapping, measuring and digging at Tikal for at least a century, they have been unsure how the settlement’s residents managed their water.

“These have been the first systematic excavations done in the reservoirs,” saidNick Dunning, a geo-archaeologist at the University of Cincinnati and a co-author of the paper.

Around 20 years ago, he recounted, Dr. Scarborough began studying maps of Tikal created in the 1960’s by researchers at the University of Pennsylvania and came up with a “fairly hypothetical” idea of how the ancient Mayans might have controlled water. “Vern has been itching to actually get to Tikal and get a chance to test some of these ideas,” Dr. Dunning said.

 Vern Scarborough, an anthropologist at the University of Cincinnati, using a sediment coring device to determine onetime water levels in the Maya reservoirs.

Four scientists, a handful of graduate students and a few dozen expert Guatemalan excavators conducted research at Tikal in the summer of 2009 and 2010 and then combined their primary findings with historical ones by other scientists, Dr. Dunning said.

In the paper, the authors describe a series of dams and reservoirs that the Maya in Tikal used to direct the water they needed for survival. The authors also describe a rudimentary but seemingly effective water filtration system they found in which the Maya used sand to sift their water.

The nearest source of sand that the researchers could find was many miles away, suggesting that the Maya probably traveled a great distance to collect the sand they used for water filtration, the researchers wrote.

“They obviously realized that in order to have water they could use, they had to keep it clean,” Dr. Dunning said. The Maya put the sand into filtration boxes at the entrance to some of the reservoirs. Water from reservoirs without filters was most likely used for agriculture.

Dr. Scarborough suggested that the most significant insight is that it allowed the Maya to successfully cope with their capricious tropical climate, one that causes floods half the year and parched dryness the other half. “It accents the cleverness and uniqueness of the ability of these indigenous folks to roll with the punches, if you will, over time,” he said.

The Maya built their reservoirs out of rock quarries from which they also cut stones for their giant temples. The holes in the ground left after the removal of the stones were perfect for filling with water.

University of CincinnatiLiwy Grazioso, a Guatemalan researcher who has taken part in the water system research, in a Maya-built canal at Tikal.

They also sealed off all the cracks and crevasses in their walkways and buildings with plaster, funneling every possible drop of water that hit Tikal into a reservoir. The reservoirs are placed on different tiers of elevation so that the Maya could use gravity to direct the water as they wished through the settlement, Dr. Scarborough said.

The researchers believe the simple “low-tech” methods used in Tikal to conserve resources to its residents could be harnessed anew as people move back into the highlands to farm today. A water system like Tikal’s doesn’t require much expertise or oversight, he noted.

“There are significant issues as to what are sustainable and what are not sustainable land use and forestry practices,” Dr. Dunning said. Given that Tikal sustained itself for over 1,000 years, current residents, many of whom are ethnic Maya, could apply such techniques to conquer some of the same problems, he said.

http://green.blogs.nytimes.com/2012/07/16/a-mayan-water-system-with-lessons-for-today/