In Jerusalem’s City of David, archaeologists have unearthed a vast ancient dam that may dramatically shift long-held timelines about biblical infrastructure.

According to CBN, archaeologists have determined the newly uncovered structure near the Pool of Siloam dates back nearly two centuries earlier than previously believed, to the era of King Joash, revealing a sophisticated public works initiative well before King Hezekiah's famed tunnel system.

The discovery was made at the southern edge of the City of David, near the historic Pool of Siloam. Widely associated with a New Testament account where Jesus healed a blind man, the area has drawn attention from both biblical scholars and archaeologists for centuries.

The dam was initially believed to be part of a system created under King Hezekiah in the late eighth century B.C., conceived as a defense against the looming threat of the Assyrian Empire. This narrative has formed a key part of Jerusalem’s biblical-era water history taught for generations.

However, with modern techniques including carbon-14 testing and advanced dating methodologies, experts have now placed its construction between 805 and 795 B.C. This re-dating indicates the infrastructure predates Hezekiah by approximately 200 years, placing it in the era of King Joash or his immediate successor.

New Timeline Suggests Joash Was a Major Builder

According to biblical texts, King Joash is known for his efforts to restore the Temple in Jerusalem, but this new finding suggests his civic projects may have been more extensive than previously thought. Danny Herman, one of the researchers involved, compared Joash’s undertakings to those of King Herod, labeling him a kind of “miniature builder-king.”

“I think we can now firmly say that after renovating the Temple, he took maybe some money left and decided to make a dam,” Herman said. “It’s a whole new understanding of Joash.” The structure's possible dual purpose — regulating daily spring water and managing flash floods — also hints at early awareness of unpredictable climatic conditions.

Historically, this dam had only been partially documented. Referred to during the 19th century as “Birket el-Hamra,” or the Red Pool, it had not been thoroughly examined or dated until now due to limits in technology and access.

Religious Property Delayed Breakthrough Excavation

The full excavation was delayed for years due to legal and property hurdles, as the land was owned by the Greek Orthodox Church. It wasn’t until the Israeli court affirmed the property's sale that digging could resume in earnest.

The turning point came in 2003 when archaeologist Eli Shukrun discovered wide steps and a large cavity, believed to be part of a ritual bath or other sacred structure. However, rather than finding more steps as expected, researchers instead revealed a gaping hole that led to the ancient dam itself.

The location is hydrologically strategic. The Gihon Spring, located nearby, was the main water source for ancient Jerusalem and was connected in earlier times via a Canaanite-era tunnel dating to the Middle Bronze Age. The newly uncovered dam likely formed a crucial component of an early water management system built around this spring.

Hezekiah’s Waterworks May Have Been Additions

Later, during the reign of King Hezekiah, Jerusalem faced threats from invaders — most notably from Assyria. To safeguard the water supply, Hezekiah expanded and secured the existing system by constructing what is now called Hezekiah’s Tunnel, or the Siloam Tunnel.

This defensive water route was designed to channel water underground to a safer location within the city walls. A 19th-century inscription found inside the tunnel celebrates its construction, though it does not name the king or detail its purpose explicitly. Nonetheless, scholars largely link it to Hezekiah using both biblical text and architectural analysis.

Herman suggested that Hezekiah’s innovations built upon earlier work. “He had some of the infrastructure already there,” he said, “and he connected the dots.” This indicates a continuity of urban development spanning generations of rulers.

Advanced Water Engineering Dates Back Further Than Thought

The functionality of the original dam, as described by experts, was both practical and forward-thinking. Designed to collect water from the Gihon Spring under normal conditions and trap flash floods during heavy rains, it shows early urban planners accounting for environmental variability.

The interdisciplinary nature of the study, combining archaeological techniques with climate science, helped contextualize the purpose of the structure. It also validated long-held, yet previously unproven, theories regarding Jerusalem's ancient water management strategies.

“Almost all scholars agree this was a project made by Hezekiah,” Herman added, “and now we have a better understanding that he was using an infrastructure set up by King Joash nearly 200 years earlier.” The revised timeline challenges previous views on the origin and evolution of the city’s engineering capabilities.

The Pool of Siloam continues to be a focal point of historical and religious interest. As excavation efforts continue, experts now see this area as a site of significant civic activity dating well before its most famous kings.

This discovery not only enriches our understanding of Jerusalem’s past but also offers a clearer picture of how biblical accounts reflect the evolving infrastructure of an ancient city striving to thrive amid political and environmental challenges.