Hi John,
I believe water traps are common on other Audi models from.this area. Am I right in thinking the battery is in the same area along the bulkhead? If so you may find a drain plug there. Also if water is to fill up then you may find wet carpets in the front footwells. This definitely applies to the c5 a6. I have seen c5 owners make custom covers for the area not covered by the plastic cover (if that makes sense?). Out of aluminum or similar.
Cheers
Steve