Mocum, waters came up and covered the city and inhabitants because of their wickedness.
covered with water, 3 Ne. 9:7
7 Yea, and the city of Onihah and the inhabitants thereof, and the city of Mocum and the inhabitants thereof, and the city of Jerusalem and the inhabitants thereof; and waters have I caused to come up in the stead thereof, to hide their wickedness and abominations from before my face, that the blood of the prophets and the saints shall not come up any more unto me against them. (3 Nephi 9)