Wait one minute...
Dawson's Creek is flimed on the University of NC at Wilmington Campus. This campus is right on the coast, hence the water scenes...since they are supposed to be on an island, right? I don't watch the show so I'm not positive, but I'm pretty positive about the UNC-Wilmington thing. Wilmington is like the Hollywood of the East Coast. Empire Records was also filmed there as well as some other films.
Just some info...