2,800-Year-Old Dam Linked to Biblical Kings Uncovered in Jerusalem

Archaeologists in Israel say they have uncovered a massive 2,800-year-old dam that was built during the reigns of biblical kings to collect water amid a severe drought. It is the largest dam ever discovered in Israel and dates to 795-805 B.C., during the reigns of either King Joash or King Amaziah, both of Judah. The dam and its function are documented in the journal PNAS by archaeologists with the Israel Antiquities Authority and the Weizmann Institute of Science.
The dam was unearthed during excavations at the Pool of Siloam in the City of David National Park. The structure is about 40 feet high and 26 feet wide, and its uncovered length reaches 68 feet, “continuing beyond the limits of the current excavation,” said excavation directors Nahshon Szanton, Itamar Berko, and Filip Vukosavović in a joint statement.
“The dam was designed to collect waters from the Gihon Spring as well as floodwaters flowing down the main valley of ancient Jerusalem (the historical Tyropoeon Valley) to the Kidron Stream, providing a dual solution for both water shortages and flash floods,” they said.
Joash and Amaziah reigned in Judah in the years following the death of Solomon, when the Kingdom of Israel was divided in two. Joash became king of Judah at age seven and, though his reign began with him doing “what was right in the eyes of the Lord,” (2 Kings 12:2) he later turned to idolatry and was assassinated by his own officials (2 Kings 12:20). Amaziah reigned after Joash, rising to the throne at age 25 and reigning for 29 years. The Bible says he “did what was right in the eyes of the LORD, but not as his father David had done” (2 Kings 14:2) -- meaning his reign was a mixture of good and bad.
Johanna Regev and Elisabetta Boaretto of the Weizmann Institute said twigs and branches embedded in the dam “provided a clear date at the end of the 9th century BC, with extraordinary resolution of only about 10 years -- a rare achievement when dating ancient finds.”
The dam was built amid a “period of low rainfall” in Israel, interspersed “with short and intense storms that could cause flooding,” they said.
“It follows that the establishment of such large-scale water systems was a direct response to climate change and arid conditions that included flash floods.”
The dam is “clear evidence” of Jerusalem’s strength and sophistication during the time, the Israel Antiquities Authority said.
WATCH: The Largest Dam in Ancient Israel was Uncovered in the City of David
Photo Credit: ©Israel Antiquities Authority
Michael Foust has covered the intersection of faith and news for 20 years. His stories have appeared in Baptist Press, Christianity Today, The Christian Post, the Leaf-Chronicle, the Toronto Star and the Knoxville News-Sentinel.
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Originally published August 29, 2025.