We need to know how people settled. Was it permanent dwellings, limited-lifespan dwellings (wattle/reed), seasonal dwellings, or nomadic dwellings. If people kind of moved from season to season, or as local resources get depleted, then water creeping up is kind of just accepted as "they way things happen." If it was settled for hundreds of years and then water crept up, sure, I can see that being considered a flood if it happened quickly enough.
I guess we may have to live with guesswork as I doubt we'll have convincing answers.
I guess we may have to live with guesswork as I doubt we'll have convincing answers.