Survival Skills and Faith Work to Build Hezekiah’s Tunnel
Excavating a tunnel through solid limestone to channel water between two points presents a daunting enterprise, especially when the tools used to relentlessly chip away the hard limestone come from a civilization dating back to 700 B.C.E. Two digging teams, starting at opposite ends of the proposed tunnel site must meet somewhere in the middle, obtaining a low-grade slope to ensure a continuous water flow from beginning to end. To further complicate the task, the work is carried out deep in the earth with minimal lighting from oil lamps and where oxygen levels are decreased. Not a simple matter. Yet that is exactly the dilemma pushed upon the small nation of Judah as they faced an inevitable siege upon their city of Jerusalem by the mighty Assyrian army.
The landscape in most areas around the Holy Land is limestone. Jerusalem was built on a sloping surface protruding from a massive limestone hill. On the western slope and separated from the city by several hundred feet lies the Gihon Spring, an area where water is pushed up from deep within the earth, providing a water source outside the city’s surrounding fortification. The vast majority of this rising water exits at the spring, however, through the years, water created more weak spots in the limestone around the Gihon Spring. These cracks extend all the way to the city of Jerusalem. The same water pressure breaks up the limestone rock even further in these cracks before reaching the surface where they form sink holes or wet beds under crushed rock piles. These wet stops scattered over the top of the limestone are called karsts.
The people of Judah knew of karst formation and realized water in the fissures below the surface found its way from the Gihon Spring to these spots and even to the Pool of Siloam inside the city walls of Jerusalem. To greatly increase the water flow during the expected Assyrian siege, they needed to build a tunnel connecting the spring and the Pool of Siloam,.
Since the siege was eminent and time critical, the tunnel had to be excavated by two teams starting at each end to divide the distance and provide twice as much space for the digging process. Modern day archeologists have discovered the tunnel length to be 533 meters long, in an “S” shaped curve with a gentle downward slope of approximately 2 meters from beginning to end. As the crow flies, the distance from the Gihon Spring to the Pool of Siloam is only 325 meters, so why not dig the tunnel in a straight line?
The “S” shape tells modern day scholars a great deal about the tunnel construction and the important role karsts played in the excavation. Knowledge of where water had risen to the surface proved invaluable to the Judean engineers. Following the cracks in the limestone as indicated by the karsts on the surface, made the labor much easier and faster for the tunnel diggers below. We believe that the enterprise was accomplished by directing the two excavating teams below in this manner. The hammering on the hard limestone deep beneath the earth could be heard by engineers above at the karst sites. The selection of particular karsts provided their road map, or tunnel path. This guided the two excavating teams on courses that would meet, allowing the precious water to flow once the makeshift dam at the Gihon Spring was removed.
Building such a tunnel demonstrated the survival skills of humankind. When women and men have faith in God, they can overcome the impossible.