Adam Clarke on 2 Chronicles 32:4

Stopped all the fountains - This was prudently done, for without water how could an immense army subsist in an arid country? No doubt the Assyrian army suffered much through this, as a Christian army did eighteen hundred years after this. When the crusaders came, in a.d. 1099, to besiege Jerusalem, the people of the city stopped up the wells, so that the Christian army was reduced to the greatest necessities and distress.