Hezekiahs Tunnel

Jerusalem, Israel
Hezekiahs Tunnel, an eighth-century-b.c. subterranean aqueduct in Jerusalem, was a magnificent engineering achievement. Teams of stonecutters, working no more than two abreast and using hand tools, cut the 1,730-foot 576-meter passageway of bedrock, probably in about seven months. Starting from both ends, between 33 and 150 feet 10 and 45 meters underground, without sophisticated surveying instruments or contact with the surface, they were able to reach a meeting point. The Canaanite citadel called Jebus stood on a slope that fell away into a deep valley outside the present-day walls of Jerusalems Old City. It had a defensible water supply upon which the conquering Israelites were to build, reaching a climax in the reign of Hezekiah, King of Judah 727 698 b.c.. Jerusalem depended on a single source of water: the Gihon or Gichon Spring. Fed from underground streams and hidden in a small cave on the citys eastern slope, it also irrigated surrounding farmland through canals built along the Kidron creek bed. Archeologists have found evidence of Canaanite fortifications designed to protect the spring. Gihons name describes its erratic nature: the Hebrew word meanseruption orgushing. Although reliably producing up to 245,000 gallons 1.1 million liters a day, the spring would flow profusely for half an hour, then reduce to a trickle for between four and ten hourslonger intervals in summer, shorter in winter. A response to siege warfare generated the sophisticated water-reticulation systems that culminated in Hezekiahs Tunnel, one of the great engineering achievements of ancient Jerusalem. Possibly as early as 1800 b.c., the Jebusites were able to reach Gihon from within their walls: a diagonal tunnel, like others in the region, followed a natural rock fissure to a point from which pitchers could be lowered to the spring. Some scholars believe that this was the passageway mentioned in the Bible, through which Joab led King Davids men into the city, which they then overthrew. It is known as Warrens Shaft, for Colonel Charles Warren, an Englishman who discovered it in 1867. The debate continues over its date and who built it. The Israelites augmented this basic system in two stages. First, they built the Siloam Shiloah Channel, probably during the peaceful reign of King Solomon 970 928 b.c.. From Gihon a part-open, part-tunneled conduit ran south along the Kidron brook to a reservoir in the HaGal Tyropoeon Valley at the southwestern corner of Jerusalem, which by then had been extended to what are now known as the Jewish and Armenian Quarters. Sluices along its eastern side had stone gates that could be opened to irrigate the gardens and fields in the valley below. Ancient Jerusalems most extraordinary hydraulic engineering projectperhaps better classified as a civil defense undertakingwas Hezekiahs Tunnel, discovered in 1838 by the American scholar Edward Robinson. Under the implacable Sennacherib 705 681 b.c., the Assyrian Empire extended from the Persian Gulf to the Black Sea, and westward to the Nile valley. His father Sargon had overrun the northern kingdom of Israel, and Sennacherib was concerned with consolidating the family conquests. Hezekiah, the charismatic ruler of the relatively puny kingdom of Judah, reassured by the prophet Isaiah that God would protect Jerusalem, stood against the Assyrian might. He stockpiled weapons and extended the citys defenses by building the 23-foot-thick 7-meter Broad Wall. And at the first inkling of invasion he had devised a measure that would help his people survive a siege. He plannedto stop the water of the springs that were outside the city [and] closed the upper outlet of the waters of Gihon and directed them down to the west side of the City of David 2 Chron. 32:30. Hezekiahs Tunnel 701 b.c., still a functioning watercourse almost 3,000 years later, connects the Gihon Spring and the Pool of Siloam or Hezekiahs Pool, specially constructed at the south end of Jerusalem, where the king had extended the outer defenses. Thus the Bible calls the poolthe reservoir between the two walls Isa. 22. The direct distance between spring and reservoir is about 1,100 feet 330 meters, but the winding tunnel is 1,730 feet 576 meters long. On average, it is about 3 feet 900 millimeters wide and varies between 3 and 9 feet in height in places, it is 150 feet 45 meters beneath the surface of the hilly city. The fall from Gihon to Siloam is about 6 feet 1.8 meters, that is, a grade of about 1 in 70. The tunnel was excavated by two groups of workers, starting at each end and cutting toward each other through the rock to eventually connect. The Siloam Tunnel Inscription, engraved on one of the walls and found in 1880, celebrated their meeting: While there were still three cubits to be cut through, [there was heard] the voice of a man calling to his fellow, for there was an overlap in the rock on the right [and on the left]. And when the tunnel was driven through, the quarrymen hewed