Mmm, Waffle House.
Ill bet that the ~3.3M population of PR could have stood hand-in-hand and formed a human chain to that water supply.
EDIT: By god, I think Ive solved the problem! Even though the airport was "inaccessible" (even by pickup truck), and obviously the port was also "inaccessible" (even by pickup truck), FEMA could have "done something more" via a flotilla from FL to PR. I picture it something like this: