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The “conduit of the upper pool” (Isaiah 7:3) was formed by Hezekiah for the purpose of conveying the waters from the upper pool in the valley of Gihon to the west side of the city of David (2 Kings 18:17; 20:20; 2 Chronicles 32:30). In carrying out this work he stopped “the waters of the fountains which were without the city” i.e., “the upper water-course of Gihon”, and conveyed it down from the west through a canal into the city, so that in case of a siege the inhabitants of the city might have a supply of water, which would thus be withdrawn from the enemy.
There are also the remains of a conduit which conducted water from the so-called “Pools of Solomon,” beyond Bethlehem, into the city. Water is still conveyed into the city from the fountains which supplied these pools by a channel which crosses the valley of Hinnom.