When children in Naples were playing in caves and tunnels under the hill of Posillipo in Italy forty years ago, they had no idea their playground was actually a Roman aqueduct.
When they recently shared their memories with archaeological authorities, it sparked an investigation into one of the Roman world’s longest and most mysterious examples of ancient water infrastructure.
The famous aqueducts of Rome supplied water for baths, drinking, public fountains, and other uses. Aqueducts built during a period of about half a millennium (roughly 300 B.C. to A.D. 200), around the former Roman Empire are highly recognizable today thanks to their multitiered arched structure. However, this ancient architectural marvel represents only a small fraction of the actual water system; the vast majority of the infrastructure remains underground.
Outside of Rome, subterranean aqueducts and their paths are much less understood. The newly investigated Aqua Augusta, also known as the Serino aqueduct, was built between 30 and 20 B.C. to connect luxury villas and suburban outposts in the Bay of Naples. Circling Naples and running down to the ancient vacation destination of Pompeii, the Aqua Augusta is known to have covered at least 87 miles (140 kilometers), bringing water to people all along the coast as well as inland.
However, the complex Aqua Augusta has barely been explored by researchers, making it the least-documented aqueduct in the Roman world. The Cocceius Association, a nonprofit group that conducts speleo-archaeological work, are bringing this fascinating aqueduct to light.
Association members discovered a branch of the aqueduct that carried drinking water to the hill of Posillipo and the crescent-shaped island of Nisida thanks to reports from locals who used to explore the tunnels as children. So far, approximately 2,100 feet (650 meters) of the well-preserved aqueduct has been discovered, making it the Aqua Augusta’s longest known segment.
According to Graziano Ferrari, president of the Cocceius Association, “the Augusta channel runs quite near to the surface, so the inner air is good, and strong breezes often run in the passages.”
However, exploring the aqueduct requires extensive caving experience. The most difficult challenge for the explorers in exploring the tunnel was to circumvent the tangle of thorns at one entrance.
“Luckily, the caving suits are quite thornproof,” he said. “After succeeding in entering the channel, we met normal caving challenges — some sections where you have to crawl on all fours or squeeze through.”
In a new report, Raffaella Lamagna, Vice President of the Ferrari and Cocceius Association, lists several scientific studies that can be done now that this stretch of aqueduct has been discovered. Specifically, scientists will be able to calculate the ancient water flow with high precision, to learn more about the eruptive sequences that formed the hill of Posillipo, and to analyze the mineral deposits on the walls of the aqueduct.
Rabun Taylor, a professor of classics at the University of Texas at Austin who was not involved in the report, told Live Science in an email that the newly discovered aqueduct section is interesting because it is “actually a byway that served elite Roman villas, not a city. Multiple demands on this single water source stretched it very thin, requiring careful maintenance and strict rationing.”
Taylor, an expert on Roman aqueducts, also said the new find “may be able to tell us a lot about the local climate over hundreds of years when the water was flowing.” This insight is possible thanks to a thick deposit of lime, a calcium-rich mineral that “accumulates annually like tree rings and can be analyzed isotopically as a proxy for temperature and rainfall,” he added.
Ferrari, Lamagna and other members of the Cocceius Association plan to analyze the construction of the aqueduct as well, to determine the methods used and the presence of water control structures. “We believe that there are ample prospects for defining a research and exploration plan for this important discovery, which adds a significant element to the knowledge of the ancient population” living in the Bay of Naples, they wrote in the report.
