Why do you think the flood myth originated in the southern Mesopotamia?

Mesopotamia arose on the land where two large rivers Tigris and Euphrates flowed, and from the south the territory of Mesopotamia was washed by the Persian Gulf. Floods often happened here, especially during the rainy season, in spring and autumn. Rivers overflowed their banks, flooding arable lands and cities. It was a real disaster for people who lost all their property. It seemed to them that God was punishing them for their bad deeds and deeds. This is how the flood myth arose.