2 Kings 20:20 Now the rest of the acts of Hezekiah and all his might, and how he constructed the pool and the conduit and brought water into the city, are they not written in the Book of the Chronicles of the Kings of Judah?
2 Chronicles 32:2-4 Now when Hezekiah saw that Sennacherib had come and that he intended to wage war against Jerusalem, (3) he decided with his officers and his warriors to cut off the supply of water from the springs which were outside the city, and they helped him. (4) So many people assembled and stopped up all the springs and the stream which flowed through the region, saying, “Why should the kings of Assyria come and find abundant water?”
2 Chronicles 32:30 It was Hezekiah who stopped the upper outlet of the waters of Gihon and directed them to the west side of the city of David. And Hezekiah was successful in everything that he did.
TUNNEL DETAILS
Date of Construction: c. 710 BC
Length: 1750 Feet (1/3 mile)
Entrance: Gihon Spring, Kidron Valley
Exit: Pool of Siloam, Central Valley
Elevation Drop: 12 inches
Height: 5 1/2 - 6 1/2 Feet along most of the length
Minimum Height: 4 Feet 9 inches
Water Depth: Generally somewhere between the ankle and the knee.
MORE INFO:
https://armstronginstitute.org/101-hezekiahs-tunnel Excellent article with pictures and graphics from the Armstrong Institute of Biblical Archaeology.
https://www.youtube.com/watch?v=NmcwiYHWpe4 An informative short video (12 minutes) describing the history and experience of walking through the tunnel.
http://coastdaylight.com/hez1.html A well-documented account from a tourist walking through the tunnel.
RECOMMENDED: There are City of David Ancient Jerusalem walking tours that take 3 hours and include Hezekiah's Tunnel and Warren's Shaft.
Warren's Shaft, named after the archeologist who discovered it in 1867, is located in the City of David next to the entrance to Hezekiah's Tunnel. It is a nearly 42-foot vertical natural shaft leading down to the Gihon Spring that gave protected access to water within the city walls. The biblical significance for this shaft is it may very well have been the shaft David's men climbed through to capture Jerusalem c. 1010 BC. ( 2 Samuel 5:1-11; 1 Chronicles 11:1-9)