The only permanent water source of the city in this period, the monumental Pool of Siloam, is clearly distinguishable in the model. It was fed by waters of the Gihon Spring diverted through Hezekiah's Tunnel, built in the 8th century BC.
The intermittent spring that constituted Jerusalem's most ancient water supply, situated in the Kidron Valley just below the eastern hill (Ophel). This abundant source of water was entirely covered over and concealed from outside the walls and was conducted by a specially built conduit to a pool within the walls where a besieged city could get all the water it needed. "Why should the kings of Assyria come and find abundant water?" the people queried in the time of Hezekiah (2 Chron 32:2-4). Hezekiah's Tunnel, 1,777 feet long, hewn out of the solid rock and comparable to the tunnels at Megiddo and Gezer, conducted the water to a reservoir within the city. From the top of Ophel the ancient Jebusites (c. 2000 BC) had cut a passage through the rock where waterpots could be let down a 40-foot shaft to receive the water in the pool 50 feet back from the Gihon. Early excavations at Jerusalem by the Palestine Exploration Fund under the direction of Sir Charles Warren (1867) resulted in finding the 40-foot rock-cut shaft. It is now known as Warren's Shaft. Conrad Shick in 1891 discovered an ancient surface canal that conveyed water from the Gihon Spring to the old pool of Siloam, located just within the SE extremity of the ancient city. Isaiah seems to have alluded to the softly flowing waters of this gentle brook when he spoke poetically of "the gently flowing waters of Shiloah" (Isa 8:6).