Facing forward,
The purpose of a rear facing scoop is to catch the cold/ clean air coming of the windshield, as in the phrase "cowl induction". From the pics it looks like the scoop is too far forward to really benefit from that effect.
I think either way will allow the hot air to escape. Facing forward will allow cold air to come in and push out the hot air underneath,
Facing back the air coming in from the grill and the rad fan will push the air out the scoop.
Why not just try it both ways before permanently mounting the scoop.
as far as water, I think if the water is above the hood line you will have bigger issues, ( been there done that)
