The rising of the Nile likely refers to the land shaking like an earthquake, moving up and down. It was common knowledge in Israel that there were times when the Nile River was in flood and where it would rise and spread out over a large area before receding. The prophet Jeremiah also uses the rising of the Nile as a picture of judgment (Jeremiah 46:7–8).1
8 Shall not the land tremble on this account, and everyone mourn who dwells in it, and all of it rise like the Nile, and be tossed about and sink again, like the Nile of Egypt?”