From The Talmud And Hebraica

"A deep bottom, called Kedron, bounds the mount of Olives, which lies against the city eastward." "They built a foot-causeway, or a foot-bridge, upheld with arches, from the mount of the Temple to the mount of Olives, upon which they led away the red cow (to be burned). In like manner, such a foot-causeway they made, upon which they led away the scape-goat: both were built at the charges of the public treasure, which was in the Temple." The reason of that curiosity concerning the red cow was this: -- when the ashes of that cow were especially purifying above all other things (for they cleansed from the uncleanness contracted by the touch of a dead person), they thought no caution enough to keep him safe from uncleanness, who was to burn the cow. When, therefore, there might be, perhaps, some sepulchres not seen, in the way he was to go, whereby he might be defiled, and so the whole action be rendered useless, -- they made him a path, at no small cost, all the way, upon arches joining to one another, where it was not possible to touch a place of burial. The like care and curiosity was used in leading away the scape-goat.

The sheaf of first-fruits was reaped from the Ashes'-valley of the brook Kedron. The first day of the feast of the Passover, certain persons, deputed from the Sanhedrim, went forth into that valley, a great company attending them; and very many out of the neighbouring towns flocked together, that the thing might be done, a great multitude being present. And the reason of the pomp was fetched thence, because the Baithuseans, or Sadducees, did not think well of doing that action on that day: therefore, that they might cross that crossing opinion, they performed the business with as much show as could be. "When it was now even, he, on whom the office of reaping laid, saith, 'The sun is set'; and they answered, 'Well.' -- 'The sun is set'; and they answered, 'Well.' -- 'With this reaping-hook'; and they answered, 'Well.' -- 'With this reaping-hook'; and they answered, 'Well.' -- 'In this basket'; and they answered, 'Well.' -- 'In this basket'; and they answered, 'Well.' -- If it were the sabbath, he said, 'On this sabbath'; and they answered, 'Well.' -- 'On this sabbath'; and they answered, 'Well.' -- 'I will reap'; and they answered, 'Reap.' -- 'I will reap'; and they answered, 'Reap.' This he said thrice; and they answered thrice, 'Well.'"

In the place, marked in the margin, they are treating concerning removing a sepulchre, seated in an inconvenient place, that it might not pollute any man. Examples are brought-in of the sepulchres of the house of David, which were moved out of their places, -- and of the sepulchres of the sons of Huldah, which were within Jerusalem, and were not moved out of their places. "Hence it appears (saith R. Akibah), that there was a certain cave, whereby filth and uncleanness was carried down into the valley of Kedron."

By such a pipe and evacuation under-ground, did the filth of the Court of the Temple run into the valley of Kedron. "The blood poured at the foot of the altar flowed into a pipe, and emptied itself into the valley of Kedron: and it was sold to the gardeners to dung their gardens."