Wednesday, June 4, 2014

Ancient Water Tunnels

By Bethany Youngblood

Roman Aqueduct
Water. One of the greatest necessities for life. A dependable and available source of clean water is as paramount a need today as it was for ancient man. The conquering Roman Empire, the philosophical Greeks, God’s chosen people in Israel, and all the dozens of other great ancient cultures; where would those peoples and their grand civilizations be without readily available water?

Of course, one could not imagine Rome without its aqueducts; those incredible feats of engineering, capable of transporting clean water from the springs in the mountains to the flourishing cities. But those amazing structures, beautiful and essential as they were to survival, were also the first things that invading armies choose to target in order to defeat their enemies. With the water supply cut off, a city’s days are numbered.

In response, great minds devised a way to protect their watery lifelines from attack in the form of tunnels. Instead of moving the water above the ground, vulnerable to destruction, the water could be moved secretly below the surface. Two ancient tunnels in particular are considered the greatest works of water engineering technology in the Pre-Classical Period: the Tunnel of Eupalinos on Samos Island, and Hezekiah’s Tunnel in Jerusalem.

The Tunnel of Eupalinos

The Eupalinos Tunnel

Travel back in time to the Greek City-State of Samos in the Eastern Aegean Sea, 530 BC.[1] The ruling tyrant Polycrates, an ambitious man of those times, built up fortifications along this island, his naval base of power. But Samos had a problem that plagued many cities in this arid terrain: a dependable source of clean drinking water. The Island of Samos did boast a natural spring, but between the spring and the city was the formidable Mt. Castro.[2] Building an above-ground aqueduct around the mountain was a possibility, however, a military minded man such as Polycrates knew that such structures were the first to be destroyed by invading hordes. So another method of moving the water across such a vast distance had to be worked out.

Polycrates turned to an engineer named Eupalinos from Megara to head a team in solving this problem. Eupalinos was the student of the “Father of Numbers”, the great mathematician Pythagoras also a native of Samos. It was Pythagoras’ famous Pythagorean Theorem that made it possible for Eupalinos to solve the problem. The geometric theorem states that in a right-angled triangle the square of the hypotenuse (the side opposite the right angle), c, is equal to the sum of the squares of the other two sides, b and a.[3]
Instead of going around the mountain, Eupalinos proposed a tunnel going straight through Mt. Castro. This would have been a lengthy and dangerous undertaking. But with enemy attacks on the island looming in the future, Eupalinos proposed an even bolder plan to speed things along. Instead of beginning at one end and exiting out the other, two tunnels would be constructed from either end and, hopefully, meet in the middle.  Eupalinos was the first to use a geometry-based approach to excavate a tunnel from both sides and if his measurements were off, the two tunnels could pass by one another and never know.

Eupalinos Tunnel
“Engineering an Empire- Greece” History Channel Documentary
Eupalinos succeeded in this enterprise by using geometry to calculate two sides of a right triangle around the mountain, so that the path of the hypotenuse would become the path of the tunnel through the mountain. Incredibly, the two tunnels connected in the middle almost exactly where Eupalinos had predicted, with only 24 inches difference between each tunnel floor where they connected.[4]

This tunnel, stretching nearly 4,000 ft.[5] from the spring to the city, took on the name of its engineer and remains one of the greatest water engineering achievements of ancient times. 

Hezekiah’s Tunnel

The second great example of water engineering lies beneath Jerusalem and was constructed even earlier than Eupalino’s tunnel, around 701 B.C, during the reign of King Hezekiah.[6]
 “Now the rest of the acts of Hezekiah – all his might, and how me made a pool and a tunnel and brought water into the city – are they not in the book of the chronicles of the Kings of Judah?” (2 Kings 20:20 NKJV) 
This tunnel was indeed documented in the Old Testament and by other sources as well. King Hezekiah had this tunnel constructed for the same reasons that Polycrates had the Eupalinos Tunnel constructed, the threat of invasion.

“And when Hezekiah saw that Sennacherib had come, and that his purpose was to make war against Jerusalem he consulted with his leaders and commanders to stop the water from the springs which were outside the city; and they helped him. Thus many people gathered together who stopped all the springs and brook that ran through the land, saying, “Why should the kings of Assyria come and find much water?” (2 Chronicles 32:2-4 NKJV)

Gihon Spring

Hezekiah had the springs outside the city blocked off so that the enemy army wouldn’t have a source of water, meanwhile, Jerusalem was being supplied by their underground water system. The tunnel’s source was the Gihon spring. This natural spring, whose name means “gushing”, is estimated to have been capable of supporting a population of 2,500 people. The tunnel itself follows an “S” shape and stretches 1,750 feet under Jerusalem, from the Gihon Spring to the Pool of Siloam.[7] This tunnel was also excavated from both sides, but followed a windy path, perhaps a natural crack in the rock, and met in the middle.

An inscription left by the workers was found in 1880 and reveals how the tunnel was cut out from the rock.

“…And this is the account of the tunneling through. While [the workmen raised] the pick each toward his fellow and while there [remained] to be tunneled [through, there was heard] the voice of the man calling to his fellow, for there was a split in the rock on the right hand and on [the left hand]. And on the day of the tunneling through the workmen stuck, each in the direction of his fellow, pick against pick. And the water started flowing from the source to the pool, twelve hundred cubits. And the height of the rock above the head of the workmen was a hundred cubits.”[8]
Wading down the length of Hezekiah’s tunnel remains a highlight of tourists in the city of Jerusalem.


The Romans, Greeks, and Jews all possessed the knowledge to change their environment to suit their needs, in this case building aqueducts or digging underground waterways. They were not the only cultures on the planet to have this knowledge either. Though we do not have time to go over them in this article, please continue to explore!
Jesus answered and said to her, “Everyone who drinks of this water will thirst again; but whoever drinks of the water that I will give him shall never thirst; but the water that I will give him will become in him a well of water springing up to eternal life.” (John 4:13-14)

[1] “Tunnel of Eupalinos” Nanos Theodore. 2012. Blog Article.

[2] “Engineering An Empire – Greece” Part 3 of 5. History Channel Documentary. YouTube.

[3] “Pythagoras of Samos” Nanos Theodore. 2011. Web Article.

[4] “Engineering An Empire – Greece” Part 3 of 5. History Channel Documentary. YouTube.

[5] Ibid.
[6] “Hezekiah’s Tunnel” Lancaster E. James. 1999. Web Article.

[7] “Hezekiah’s Tunnel” Web.

[8] “Hezekiah’s Tunnel” Lancaster E. James. 1999. Web Article.

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