Someone will breach the Aswan dam and Lower Egypt will be washed away down to the rocks. This is not prophecy - just a common sense conclusion when you have a massive lake behind a dam at the mercy of the millions of crazies that live in the Middle East.
That scenerio doesn’t desolate the land for 40 years though. Why does the author assume that the end of the 40 years will occur during the 1000 year reign? I’m not being snarky, just curious.