Hezekiah's Tunnel - Function and Origin

Function and Origin

The ancient city of Jerusalem, being on a mountain, is naturally defensible from almost all sides, but suffers from the drawback that its major source of fresh water, the Gihon spring, is on the side of the cliff overlooking the Kidron Valley. This presents a major military weakness as the city walls, if high enough to be defensible, must necessarily leave the Gihon spring outside, thus leaving the city without a fresh water supply in case of siege.

The Bible says that King Hezekiah (c. 8th century BC), fearful that the Assyrians would lay siege to the city, blocked the spring's water outside the city and diverted it through a channel into the then Pool of Siloam. However, it is now known (as of 1997) that the earlier Warren's shaft system had already heavily fortified the Gihon Spring; Warren's shaft is not an aqueduct, and requires those desiring water to travel up and down it themselves - an arrangement that Hezekiah seemingly must have considered inadequate.

In 1899, an ancient channel, also leading from the Gihon Spring to the Siloam Pool area, but by a more direct route, was found. This channel is now known as the Middle Bronze Age channel, on account of its estimated age. Ronny Reich determined that it was constructed around 1800 BC (in the Middle Bronze Age), and thus that the spring's water had already been diverted many centuries before Hezekiah. As originally constructed, it is understood as a 20 feet deep ditch in the ground, covered over by large rock slabs (which were then hidden in the foliage). It is narrower than the tunnel, but can still be walked by a human for most of its length. In addition to the (3 ft high) exit near the Siloam pool, the channel has several small outlets that watered the gardens facing the Kidron Valley. Hezekiah's tunnel was constructed to replace this channel, since a besieging army could fairly easily have discovered and destroyed the Middle Bronze Age Channel.

Hezekiah's tunnel, discovered in 1838 by the American biblical scholar Edward Robinson, can be walked through today from end to end.

The Bible verses relating to Hezekiah's tunnel are these:

"As for the other events of Hezekiah’s reign, all his achievements and how he made the pool and the tunnel by which he brought water into the city, are they not written in the book of the annals of the kings of Judah?" 2 Kings 20:20

"When Hezekiah saw that Sennacherib had come and that he intended to wage war against Jerusalem, he consulted with his officials and military staff about blocking off the water from the springs outside the city, and they helped him. They gathered a large group of people who blocked all the springs and the stream that flowed through the land. 'Why should the kings of Assyria come and find plenty of water?' they said." 2 Chronicles 32:2-4

"It was Hezekiah who blocked the upper outlet of the Gihon spring and channeled the water down to the west side of the City of David. He succeeded in everything he undertook." 2 Chronicles 32:30