A large rock-hewn water reservoir dating to the First Temple period was discovered in the archaeological excavations that are being conducted in the Jerusalem Archaeological Garden, at the foot of Robinson’s Arch near the Western Wall Plaza. According to archaeologists, the reservoir and a channel leading into it may be one mentioned in the Book of Joel.

The excavation, during the course of which the reservoir was discovered, is part of an archaeological project, in which the entire drainage channel of Jerusalem dating to the Second Temple period is being exposed.

The channel runs from the Shiloach (Siloam Pool) to a point beneath Robinson’s Arch. The route of the channel was fixed in the center of the main valley that extends from north to south over the length of the ancient city, parallel to the Temple Mount. In his description of Jerusalem during the Second Temple period, Josephus refers to the valley by its Greek name “Tyropoeon,” which scholars believe means “Valley of the Cheese-makers.” Another interpretation identifies the valley with the “Valley of the Decision,” mentioned in the Book of Joel.

It became apparent while excavating the channel that during the construction of this enormous engineering enterprise, its builders had to remove earlier structures that were situated along the route of the channel and “pass through” existing rock-hewn installations that were located along it. An extraordinary installation that was exposed in recent weeks is a large water reservoir treated with several layers of plaster, which probably dates to the First Temple period.

The reservoir has an approximate capacity of 250 cubic meters and is therefore one of the largest water reservoirs from the First Temple period to be discovered so far in Jerusalem. Presumably it was used by the general public.

The excavations at the site are being carried out by the Israel Antiquities Authority, underwritten by the Ir David Foundation and in cooperation with the Nature and Parks Authority. The reservoir will be officially presented Thursday, together with other finds from this past year at the 13th annual conference on the “City of David Studies of Ancient Jerusalem,” to be held in Jerusalem.

According to Eli Shukron, the excavation director on behalf of the Israel Antiquities Authority, “to the best of our knowledge this is the first time that a water reservoir of this kind has been exposed in an archaeological excavation. The exposure of the current reservoir, as well as smaller cisterns that were revealed along the Tyropoeon Valley, unequivocally indicates that Jerusalem’s water consumption in the First Temple period was not solely based on the output of the Gihon Spring water works, but also on more available water resources such as the one we have just discovered.”

Antiquities Authority officials said that the group was preparing to open up part of the find to visitors.