Thousands of bites from hundreds of cottonmouths just hanging around invibly below the surface?

That never happened. It's an urban (rural) legend.

But if it helps you pay attention to the world and not blunder through life like the idiots who cross the road staring into their mobile phones, great.

I live with snakes, I know them and I get pissed when they get demonised.

Water moccasins hunt primarily at night. They don't do it in groups. They may form mating aggregations, but these will be on the surface and be quite visible.

This is a list of US snakebite deaths

https://en.wikipedia.org/wiki/List_of_fatal_snake_bites_in_the_United_States

It's probably not complete, but you won't find a cottonmouth/moccasin on it. Still I strongly advise not to get bitten!

The world is beautiful and it has many teeth.