As you read this story, you will learn the following:
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The Ain Brak Aqueduct that supplied water to ancient Petra was thought to have only one pipe or channel until a second one was recently discovered.
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Although most of the lead pipes are no longer present in the conduits, their former extent can be inferred by matching their imprints to fragments of lead pipes still present in the area.
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The pipe is long and narrow and was likely used as an inverted siphon, with water passing through a collection tank before flowing to a series of reservoirs.
The importance of finding water in a harsh desert climate is a central theme in Frank Herbert’s classic science fiction novel dune (And Denis Villeneuve’s latest film adaptation). Rising out of dusty sand and carved from red sandstone, the ancient Jordanian city of Petra is reminiscent of the desert landscapes and stone architecture of Herbert’s distant sci-fi desert planet. But Petra already had aqueducts and a water system thousands of years ago, far ahead of anything on fictional Arrakis, so no one in Petra needed a still suit to survive.
Petra was the urban center of the ancient world, despite its semi-arid climate with almost no rainfall. It remained the capital of the Nabataean Kingdom until it became part of the Roman province of Arabia in the early 2nd century AD. As an important administrative and trade center, Petra needed water in addition to sustaining its people. Its hydraulic system filled baths, enabled gardens and agriculture to flourish, gushed from sacred fountains called water lilies, and filled pools in temples, sanctuaries, and tombs. Now, on the southeastern edge of the abandoned city, archaeologists have discovered that the Ain Braq aqueduct that crosses the Jabal al-Madhbah massif into Petra is more complex than they previously thought.
As part of excavations carried out in 2023 as part of the Ancient Petra Urban Development Project, a research team led by Niklas Jungmann of Humboldt University Berlin studied the system for bringing water into Petra. These include cisterns, basins, reservoirs with dams and the Ein Brak Aqueduct. During the course of their research, Jungmann and his team discovered something that the aqueduct had hidden for thousands of years. It has not just one, but two different main pipes that allow water to flow into Petra. Researchers have long known of the first waterways laid with terracotta pipes that brought water into the city. What the researchers didn’t expect was that they found imprints of a second pipeline, a pressurized lead pipe that once supplied water to basins and reservoirs on Mount Zantul.
“The discovery of numerous water structures, as well as putative aqueducts and dams, on the plateau just above the rocky slope raises broader questions about the engineering and chronology of the area,” Jungmann said in a recent study published in the journal Nature. Levant. “As [the existence of a second conduit] It was not mentioned in previous studies, so studying how the aqueduct entered the city became a main research goal. “
The newly discovered pipeline is about 380 feet (116 meters) long and uses welded metal pipes made of lead and encased in mortar. Further evidence of the Nabataean use of lead pipe in the second pipeline includes its significantly larger diameter compared to clay pipes found in the area, and the regular surface of the imprint it left on the underlying stone, rather than the irregular surface imprint typical of clay pipe channels. A later excavation supported this hypothesis, with blocks of Nabataean pipes discovered during a survey of the city center. There was a length of lead pipe in the hardened mortar, the texture and dimensions of which were imprinted matched those found earlier, and there was no longer any doubt as to the overall composition of the aqueduct’s second main pipe.
Jungmann concluded that such a long and narrow lead pipe might have been used as an inverted siphon within the Ein Brak Aqueduct. It is buried in concrete to transport water beneath the city, bypassing surface barriers. Water in the system flows through a header tank before entering the aqueduct’s two pipes. Previously, one theory suggested that the pipeline may take a detour to supply water to another part of the city before reaching its destination. However, it was discovered that the pipeline extended westward, possibly to the reservoir at Mount Zantul. A bypass is not even feasible, since only uninterrupted pipes that generate sufficient internal pressure can allow the water in the siphon to flow from the header tank to the pool or reservoir to be filled.
“Overall, this study highlights the potential for further research into Nabataean water management,” Jungmann said. “While some hypotheses have been suggested above regarding the two branches of the aqueduct into the city, more field work is needed to gain a more complete understanding of the distribution system and its evolution over time.”
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