Ancient Technology in the Bible: Hezekiah’s Tunnel

Hezekiah’s Tunnel נקבת השילוח see the clear water he’s wading through? photo credit: Tamar Hayardeni

And the rest of the acts of Hezekiah, and all his might, and how he made a pool, and a conduit, and brought water into the city, are they not written in the book of the chronicles of the kings of Judah? II Kings 20:20

When I was a girl I heard that they had found the “conduit” this verse talks about under the old city of Jerusalem.  My mom told me how they found a plaque at the point where the diggers had met in the middle.

Just a couple of years ago there was a lengthy article about this tunnel in the Biblical Archeology Review magazine (not run by Christians, but way cool anyway!).  Since I can’t mail you all copies of the article, this webpage  with responses from BAR (the important bits are the responses by Ayreh Shimron) which is pretty interesting and give you the basic idea.

One of the things I spotted on that page was that portions of the tunnel is “karstic.”  Three months ago my eyes would have glazed over and it would have been a mystery.  Now we know what Karst is, so we know what they’re talking about!

The rock in those sections is Limestone that the water had been wearing away.  This might have been how David had gotten into the city to take it long before.  Have a look at this verse:

And David said on that day, Whosoever getteth up to the gutter [a hollow water space], and smiteth the Jebusites,… he shall be chief and captain.
9  So David dwelt in the fort, and called it the city of David. And David built round about from Millo and inward.  II Samuel 5:8a,9
If you blink (or yawn), you would miss that detail, but it’s interesting to know that there was already a waterway running through the hilltop of Jerusalem.

Hezekiah’s Tunnel map (blue line=tunnel, brown=elevation) photo credit: Tamar Hayardeni

Now we come 300 years later and Hezekiah is trying to make sure his people will have water even if the Assyrians lay siege to the city.  So he has two groups of miners bring all the water from the spring of Gihon through the tunnel and down into a pool around the corner of the city.   One starting from the spring and the other starting at the pool of the Siloam (which was already fed by the old channel).

We still don’t understand all the details, but we can follow the path straight west where it was a good 50m [164ft] below ground level.  Besides having some effective tools to help guide them in the direction and level they wanted to dig in, there are people who think they probably used some sounds to guide them.

The theory goes like this.  People on the surface would tap at a point in front of the miners who would listen for the general direction they were to head in.  Shimron suggests this is why they decided to head back to a point closer to the surface to continue their diggings.

Things didn’t go perfectly for the diggers.  There are several points in the tunnel where they dug in one direction and then backed up about 2m [6ft] to continue in another direction.

Some people consider the extra length of the tunnel as proof that the miners weren’t too smart.  But we have yet to figure out how the two teams of diggers were able to meet with the precision that they showed at the join.

To honor this accomplishment, they carved a memorial that was found in 1880 by a boy exploring the tunnel.  Now this plaque has been removed and is at the Istanbul Archeological Museum, but it’s real!  Here’s the translation:

Original Inscription at the Istanbul Archeological Museum (you can see why there are so many dots in the translation)

… the tunnel … and this is the story [the thing – “dvar”] of the tunnel while … the axes were against each other and while three cubits [were left] to cut? …the voice of a man … called to his fellow, for there was a through-passage [“Zedah”] in the rock, from the right … and on the day of the tunnel [being finished] the tone hewers struck [literally “hit”] each man towards his fellow, ax against [literally: “on”] ax, and the water went from the source to the pool for two hundred and a thousand cubits. and one hundred (?) cubits was the height over the head of the stone hewers.

BTW this tunnel ended at the Pool of Siloam that was only rediscovered with its original location and size  in 2005.

 He took counsel with his princes and his mighty men to stop the waters of the fountains which were without the city: and they did help him.
So there was gathered much people together, who stopped all the fountains, and the brook that ran through the midst of the land, saying, Why should the kings of Assyria come, and find much water?

This same Hezekiah also stopped the upper watercourse of Gihon, and brought it straight down to the west side of the city of David. And Hezekiah prospered in all his works. II Chronicles 32:3,4,30

For more, see the Quotes post.