Flodding on rivers is caused by human activity rather than natural events true or false

True

Explanation:

While I believe it's a compendium of the both(both true and false), I when asked to pick just one, I would go with yes. They're are lots of things we humans do on a general note that causes flooding. Although, heavy rainfall can also cause flooding and that's not as a result of human activity, but directly. But then, activities like not maintaining a dam, or erecting a structurally failed dam can cause flood to occur at any point in time, without warning even. Another way is when due to our activities, we block the rivers, this can also lead to flooding exactly like the case of heavy rainfall does. Lack of good drainage facilities, drainage wouldn't create itself, we as humans do. When we don't were essentially creating an excuse for an eventual happening of flood.

Succinctly put, human activities also cause floods, as much as natural events causes flood.