The Laver in Herod's Temple by Edersheim

Between the altar and porch of the Temple, but placed towards the south, was the immense laver of brass, supported by twelve colossal lions, which was drained every evening, and filled every morning by machinery, and where twelve priests could wash at the same time. Indeed, the water supply to the Sanctuary is among the most wonderful of its arrangements. That of the Temple is designated by Captain Wilson as the 'low-level supply,' in contradistinction to the 'high-level aqueduct,' which collected the water in a rock-hewn tunnel four miles long, on the road to Hebron, and then wound along so as to deliver water to the upper portion of the city. The 'low-level' aqueduct, which supplied the Temple, derived its waters from three sources--from the hills about Hebron, from Etham, and from the three pools of Solomon. Its total length was over forty miles. The amount of water it conveyed may be gathered from the fact that the surplusage of the waters of Etham is calculated, when drained into the lower pool of Gihon, to have presented when full, 'an area of nearly four acres of water.' And, as if this had not been sufficient, 'the ground is perfectly honeycombed with a series of remarkable rock-hewn cisterns, in which the water brought by an aqueduct form Solomon's Pools, near Bethlehem, was stored. The cisterns appear to have been connected by a system of channels cut out of the rock; so that when one was full the surplus water ran into the next, and so on, till the final overflow was carried off by a channel into the Kedron. One of the cisterns--that known as the Great Sea--would contain two million gallons; and the total number of gallons which could be stored probably exceeded ten millions.' There seems little doubt that the drainage of Jerusalem was 'as well managed as the water supply; the mouth of the main drain being in the valley of the Kedron, where the sewerage was probably used as manure for the gardens.'