Water: The Key to the Working of Herod's Temple
Updated: May 11
Painting of William Simpson from 1870 showing the largest cistern under the Temple Mount.
Water was an essential need for operations of the Temple in Jerusalem. Priests needed to be cleansed daily. The blood from sacrifices needed to be washed from around the altar. On feasts days a lot of water was needed to wash away a lot of blood. Given the Mediterranean climate and months without rain, water could not be guaranteed on any given day, and so needed to be stored. The most common way to do this in the region was by use of cisterns, which would receive rain runoff from the surface and hold it underground for later use. It turned out the Temple Mount was a great terrain for cisterns. Not only was the limestone rock soft enough for carving out openings, but a few natural caves already existed underground that could be enhanced for water storage. Not all cistern water was useful at a temple though. Sanctification water for purification was required to be “living” water—moving water—such as that issuing from a spring in the ground. It could not be simply pulled from a cistern where it might have sat for days and become contaminated. To this end the Gihon Spring became a center for priests to be washed, as it was the only reliable spring within miles. Purification at the Gihon Spring, though, required an uphill trip afterward to the Temple—and many Jews made this inconvenient trip over the centuries. To supply this demand for water at the Temple, aqueducts were constructed to bring water on a continual basis the ten or more miles from Bethlehem to Jerusalem. The open cisterns there collecting water from the mountain rains are called Solomon’s Pools, after the tradition of their original builder. Although the stonework and of the remaining aqueduct sections point to a Hasmonean construction in the 2nd century BCE and Roman improvements during their rule. Two aqueducts can be traced to Jerusalem—an “upper” and a “lower”—the latter which ended at the Temple Mount on the bridge atop of Wilson’ Arch.
Charles Wilson and Charles Warren were charged with surveying the water resources of Jerusalem in the mid-1860’s (see earlier blogs), and this gave them the opportunity to investigate all the cisterns they could find on the Temple Mount. See the map Wilson constructed below. Over thirty cisterns and subterranean tanks were found of all different shapes and sizes. The largest, called the “Great Sea” for its sheer size, shown above, is believed to hold up to 3 million gallons (over 4 Olympic-sized swimming pools). It is cistern number 8 in the southern part of Wilson’s map below. It appears to be a natural cave excavated further for water storage, with rock pillars left for support. There have also been reported visible connections there at its roof to the surface platform. Today it lies directly in front of the Al-Aqsa Mosque. It was hard for me to imagine standing at that place last year that there was such an enormous cavern present out of sight under my feet.
An important detail to note is that if one locates Herod’s Temple Sanctuary in the SW corner of the Mount today, that its eastern section falls directly over the Great Sea and the smaller cistern number 9 to its south. The positioning of these cisterns is additional evidence for the location of Herod’s Temple being exactly as that discussed in my previous blogs. The Talmud speaks of a water wheel the priests had in use in the Second Temple to bring water to the surface every morning from a major cistern directly below the Temple—water that was delivered by an underground conduit from the aqueduct and kept moving in and out of the cisterns so to remain “living”. Water wheel technology at the time was typically a number of small buckets tied to a long rope that hung over a vertical wheel down into the cistern below the water line. Turning of gears at the surface continually brought water up from the cistern via the string of buckets. Today the Al-Kas fountain also exists within the past Temple Sanctuary grounds, and it is exactly on a line between the end of the aqueduct and the Great Sea. It is the open circle on Wilson’s map at the end of the diagonal line. It is interesting to speculate if the Muslims did not make use of an existing vertical shaft that intersected water being delivered to the Great Sea. This could be another potential location within the Temple where “living” water might have been extracted from below. It is certainly delivering water there today for visitors to cleanse themselves with. See photo at the end.
1864 Map of Charles Wilson of cisterns beneath the Temple Mount.
The Al-Kas fountain today on the Temple Mount. Note the seats all around where worshippers can sit and cleanse themselves with the water from each spigot opposite the seat.