Hezekiah’s design on the tunnel plus the pool came at any given time when the city needed safety towards Assyrian invasions, as recorded in 2 Kings and a pair of Chronicles. Nehemiah three:fifteen mentions the “Pool of Shelach” (another kind of the title) through the article-exilic restoration of Jerusalem’s partitions https://siloamschool59268.ampedpages.com/the-best-side-of-siloam-digital-62958150