Archaeologists have uncovered a nearly 2,800-year-old dam near Jerusalem’s Pool of Siloam, the site where Jesus famously healed a blind man according to the Gospel of John. The discovery, made during excavations in the Jerusalem Walls National Park, adds to the growing body of evidence that the ancient city was a hub of advanced engineering and water management. The dam, dating to the ninth century B.C., is the largest ever found in Israel and the oldest in Jerusalem, with researchers attributing its construction to the reigns of King Joash or King Amaziah. The structure, measuring 39 feet in height, 69 feet in length, and 26 feet in width, is a testament to the ingenuity of ancient builders.
The dam was identified as a response to the environmental challenges of the time, including persistent droughts and intense seasonal flooding. Its primary function appears to have been the collection of water from the Gihon Spring, a critical water source for ancient Jerusalem, as well as capturing flash floodwaters from the main valley. Analysis of the materials used in construction, including twigs and branches embedded in the mortar, allowed researchers to narrow the dam’s construction date to between 805 and 795 B.C. This precision in dating highlights the sophistication of the excavation team, which includes the Israel Antiquities Authority (IAA) and the Weizmann Institute of Science. Their findings were published in the prestigious journal Proceedings of the National Academy of Sciences (PNAS), underscoring the global significance of the discovery.
Experts described the dam as a