Gone with the Flow: Ancient Andes canals irrigated farmland
By Bruce Bower
Archaeologists working in a valley on the western slopes of Peru’s Andes mountains have discovered the earliest known irrigation canals in South America, a find that illuminates the origins of large-scale agriculture in the New World.
Tom D. Dillehay of Vanderbilt University in Nashville and his colleagues came across three buried canals, stacked one on top of the next, on the southern side of a river running through the Zana Valley. Radiocarbon measurements of carbon fragments date the bottom canal to about 5,380 years ago, the researchers report in an upcoming Proceedings of the National Academy of Sciences. They estimate the ages of the middle and top canals at around 4,390 years and 1,190 years, respectively.