Charles H. Spurgeon on Psalms 137:2

"Willows." All the flat, whereon Babylon stodd, being by reason of so many rivers and canals running through it made in many places marsh, expecially near the said rivers and canals, this caused it to abound much in willows, and therefore it is called in Scripture the "Valley of Willows"; for so the words in Is 15:7, which we translate "the brook of the willows, "ought to be rendered. —Humphrey Prideaux (1648-1724), in "The Old and New Testament Connected," etc.