A large percentage of water will flow off the windshield area into the plenum chamber drain system and then down the outside on the plenum to the underside of the vehicle. To ensure that the plenum chamber water management system performs properly, the plenum water deflector, plenum chamber, and drains must not be blocked with debris.
In the graphic below the arrows show the water flow direction in the plenum chamber and drains system.
The plenum chamber is located in front of the windshield and below the plenum water deflector.