For the waters of Nimrim - It is supposed by some that the prophet here states the cause why the Moabites would flee to the cities of the south, to wit, that the “waters” of the northern cities would fail, and the country become desolate, and that they would seek support in the south. But it is more probable that he is simply continuing the description of the desolation that would come upon Moab. Nimrah, or Beth Nimra, meaning a “house of limpid waters,” was a city of Reuben east of the Dead Sea (Numbers 32:3; compare Jeremiah 48:34). It was, doubtless, a city celebrated for its pure fountains and springs of water. Here Seetzen’s chart shows a brook flowing into the Jordan called “Nahr Nimrim, or Wady Shoaib.” ‘On the east of the Jordan over against Jericho, there is now a stream called Nimlim - doubtless the ancient Nimrim. This flows into the Jordan, and as it flows along gives fertility to that part of the country of Moab.’ (Eli Smith.) It is possible that the waters failed by a common practice in times of war when an enemy destroyed the fountains of a country by diverting their waters, or by casting into them stones, trees, etc. This destructive measure of war occurs, with reference to Moab, in 2 Kings 3:25, when the Israelites, during an incursion into Moab, felled the fruit trees, cast stones into the plowed grounds, and “closed the fountains, or wells.”
For the hay is withered away - The waters are dried up, and the land yields nothing to support life.