Gihon Spring in Wikipedia

The Gihon Spring was the main source of water for the City of David, the original site of Jerusalem. One of the world's major intermittent springs - and a reliable water source that made human settlement possible in ancient Jerusalem - the spring was not only used for drinking water, but also initially for irrigation of gardens in the adjacent Kidron Valley which provided a food source for the ancient settlement. The spring being intermittent required the excavation of the Pool of Siloam which stored the large amount of water needed for the town when the spring was not flowing. Three main water systems allowed water to be brought from the spring to the city under cover: The Middle Bronze Age channel - a fairly straight channel dating from the Middle Bronze Age, cut 20 feet into the ground, and then covered with slabs (which themselves were then hidden by foliage). This led from the spring to the Pool of Siloam and was an aqueduct. Warren's Shaft - a steep tunnel, dating from slightly later than the Middle Bronze Age channel, leading from the Well Gate at the top of Ophel above Gihon, down to the spring. This passage was for people to travel down in person and collect water from the spring themselves. Hezekiah's tunnel - a winding tunnel carved into the rock, leading from the spring to the Pool of Siloam. Dating from the time of Hezekiah, and seemingly built in response to the threat of siege by Sennacherib, it was an aqueduct that effectively replaced the Middle Bronze Age channel. In 1997, while a visitor centre was being constructed, the spring was discovered to have been heavily fortified since the Middle Bronze Age, when archaeologists unexpectedly uncovered two monumental towers[1] - one protecting the base of Warren's Shaft, and the other protecting the spring itself. Due to the area around the site still being inhabited, and hence not excavated, it is unknown whether any further fortifications exist (though a further tower to the south of that protecting Warren's Shaft is thought likely). During an archaeological dig in 2009, a fragment of a monumental stone inscription securely dated to the eighth century BCE was discovered. Although only fragments of Hebrew lettering survive, the fragment proves that the city had monumental public inscriptions and the corresponding large public buildings in the eighth century.[2] The city government of Jerusalem has proposed to restore the valley floor by replacing illegally built housing with a park called the Garden of the King through which the waters of Gihon could flow south along their ancient course.[3][4]