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（最重要的） 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 dam -- 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 water in a human-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.

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

An example of the thick vegetation common in the area where a UC-led team worked in and around Tikal.

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."