It could kill them
according to the flood history in the book of Genesis, only 8 survived that.
malaria
they didn't at all
If the flood already came then the best thing to would be to go to the highest level of your house, apartment, or condo.
No
they affect harvesting and the flood.
Simply put: Because Centralia is built on a flood plain. A better question would be: Why did people build on a flood plain?
They can raise the sea levels and permanently flood coastal cities and croplands.
Water everywhere
There would be no land animals or people, since all would have perished in the Flood.
a flood plain should be protected or else people would build on one and won't survive
The flood deposited silt in the farming fields which provided fertilizer. Once the flood waters receded the fields were ready to plant.