Does this intake go to the plenum and if so how does water stay out

Which intake?

Which intake?

I think the OP is referring to the one under the cowl where the air comes in from.

If that is the question...

There is a metal stack, welded to cowl substructure that keeps water from flowing into the fresh air intake. There is a flat piece of metal welded above it to prevent water from dropping into the stack

What is this hole for in the passenger fire wall. Also is the blower housing suppose to be open like this?