(JNS) The largest dam in ancient Israel, uncovered just outside the walled Old City of Jerusalem, has been dated back to the time of the biblical kings, some 2,800 years ago, the Israel Antiquities Authority (IAA) announced on Monday.

The monumental dam, which runs about 12 meters high, more than 8 meters wide and 21 meters long, was excavated over the last two years in the history-rich ancient City of David.

A new study carried out jointly with the Weizmann Institute of Science concludes that the barrier constructed to both hold back water and raise its level was built around 800 BCE, and dates it to the reign of the kings of Judah, Joash or Amaziah, making it the earliest one ever found in Jerusalem, the state-run archaeological body said.

The researchers at Weizmann employed high-precision radiocarbon dating to unequivocally determine that this was the structure used in the construction of the Siloam Pool, which until now was only described both in the Bible and in historical sources.

“The dam was designed to collect waters from the Gihon Spring as well as floodwaters flowing down the main valley of ancient Jerusalem to the Kidron Stream, providing a dual solution for both water shortages and flash floods,” the excavation directors said.

The newly uncovered structure joins two other water systems from the same period discovered in the City of David, reflecting comprehensive urban planning for managing Jerusalem’s water supply as early as the late ninth century BCE and serves as clear evidence of the city’s power and sophistication even then, the IAA said.

“This is one of the most impressive and significant First Temple-period remains in Jerusalem, and has been preserved to an extraordinary degree,” said Eli Escusido, director of the IAA. “The revealed dam is awe-inspiring and opens new avenues of research.”

The new study will be presented at the annual City of David conference in Jerusalem in September.

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