2 Chronicles 32:4, 30, 32

They organized a huge work crew to stop the flow of the springs, cutting off the brook that ran through the fields. For they said, “Why should the kings of Assyria come here and find plenty of water?”

He blocked up the upper spring of Gihon and brought the water down through a tunnel to the west side of the City of David. And so he succeeded in everything he did.

The rest of the events in Hezekiah’s reign and his acts of devotion are recorded in The Vision of the Prophet Isaiah Son of Amoz, which is included in The Book of the Kings of Judah and Israel.