Providing water to Israel’s mountaintop capital city has been problematic since Biblical times. Israel is about to complete a massive project to solve this dilemma and part of the solution was the same used by King Hezekiah; tunneling through mountain rock.
Mekorot’s Fifth Line Water From the Mediterranean to the Holy City
Mekorot, Israel’s water company, is about to complete its ambitious Fifth Water Line to Jerusalem project that will connect the capital city to the desalination plants on the Mediterranean Coast. This was one of Israel’s largest infrastructure projects in recent years.
The soon-to-be-complete 25-mile pipeline is the second half of the project. It will enable Mekorot to quadruple its water deliveries to Jerusalem, increasing flow from 414,000 cubic meters a day to 1.66 million cubic meters a day. There are also plans of exporting water to Jordan. The project required boring a 3.5-meter diameter for 13-kilometers, the longest of its type in Israel. The entire pipeline system must be pressurized at 290 to 580 pounds per square inch (psi) to deliver the water. The water is pushed from sea level to an altitude of 900 meters via the tunnel using innovative high-pressure water technology at pumping stations positioned at every 200–250 m (656–820 feet) in elevation. The tunnel was necessary to minimize the pipeline’s environmental impact on the Jerusalem Hills and nature reserves in the area. Adjacent to the pumping stations are large reservoirs allowing the pumps to operate at times when electricity is available at cheaper rates since operating the pumps requires large amounts of electricity.
The previous “fourth line” began operation in 1984 but subsequent waves of “olim” (immigrants) in the early 1990s made it clear that more substantial water infrastructure was needed to meet the demands of the growing population. The new line was completed at a cost of 2.5 billion NIS and is intended to meet Jerusalem’s needs for the next 50 years.
The new line was begun in 2009 and is expected to begin full operations in August.
Hezekiah: Tunneling Through Rock
Close to 80 percent of the drinking water in Israel is desalinated seawater—one of the highest levels of any country in the world. This is essential for the modern city as the only natural source of water that was used in Biblical times came from the Gihon Spring above the Kidron Valley. Water flowed from the spring along Hezekiah’s Tunnel to the Siloam Pool. The Hebrew name of the spring is derived from the verb meaning “to gush forth,” reflecting the flow of the spring, which is not steady, but intermittent, its frequency varying with the seasons of the year and annual precipitation.In times of war and siege, the City of David’s water supply was vulnerable, since the Gihon spring in the Kidron Valley was outside the city walls. For this reason, King Hezekiah end of (8th century BCE) constructed an impressive water system cut into the rock beneath the City of David, in a 533 meter long, “S”-shaped course.