Gihon Spring

The Gihon Spring is a vital water source located in the Kidron Valley. It served as the primary water supply for the Pool of Siloam in Jebus. This area was part of the City of David, which was the original site of Jerusalem. Because of this reliable water, humans were able to establish permanent settlements in ancient Jerusalem. The spring is considered one of the world's major intermittent springs. This means the water does not flow at a constant rate.

The spring's flow changes depending on the season. In the winter, the water used to flow three to five times a day. During the summer, it flowed twice daily. In the autumn, it flowed only once per day. This pattern was likely caused by a siphon mechanism in the reservoir outlet. To manage this intermittent flow, people excavated the Pool of Siloam. This pool acted as a storage system for the town. It held large amounts of water for use when the spring was not flowing.

Ancient engineers developed three main water systems to transport water safely. These systems used natural paths, masonry, or rock-cut structures to provide cover. The first was the Middle Bronze Age Siloam Channel. This was a straight aqueduct cut 20 feet into the ground. It was covered with stone slabs and hidden by foliage. This channel led from the spring to the Upper Pool of Siloam.

A second system was the Bronze Age Warren's Shaft system. This consisted of tunnels dating to slightly after the Middle Bronze Age channel. These tunnels led from the Well Gate at the top of Ophel down to the spring. This allowed people to collect water directly. A third system was the Iron Age Siloam Tunnel. This was a winding tunnel carved into the rock. It functioned as an aqueduct that eventually replaced the older Middle Bronze Age channel. An inscription was even found carved into its walls.

The Gihon Spring has several names and deep historical roots. The name Gihon may come from the Hebrew word "Giha," meaning "gushing forth." It is also called the Fountain of the Virgin. This name comes from a legend where Mary washed the swaddling clothes of Jesus. The spring is extremely productive for its region. It produces 600,000 cubic meters of water every year. In comparison, the Lifta spring in West Jerusalem produces only 125,000 cubic meters.

Archaeologists have uncovered evidence of heavy fortification at the site. During excavations in 1997, researchers found two monumental towers. One tower protected the base of Warren's Shaft. The other tower protected the spring itself. There is ongoing scientific debate regarding the age of these structures. A 2017 study using 14C dating suggested the fortifications might date to the 9th century BCE. However, some scholars argue they belong to the Middle Bronze Age. They believe the samples might have been moved by flooding or later renovations.

The history of the spring also includes modern conflict. In May 1948, during the Arab–Israeli War, Israeli forces conducted Operation Cast Thy Bread. This was a biological warfare strategy. Forces under Yigael Yadin poisoned either the spring or the Pool of Siloam. They used typhus and diphtheria bacteria. The exact location of the poisoning remains unknown. This event highlights how critical this water source has remained throughout human history. Today, the spring is under the control of the Israeli organization Ir David Foundation. It is sometimes used by Jewish men as a ritual bath, known as a mikvah.