Gotta give it to Popeye. It was very close but I just don't really think of Splash as a water ride but more of a timeless disney dark ride with a thrill. To me it is about as much of a water ride as Pirates is.
Popeye is the best rapids raft ride ever built in quanity of gags, quality of gags and theming. The thing goes into the lagoon and back out again and just when you think it is over there is another gag around the corner. Also things like the animated figures below Me Ship, The Olive and Me Ship the Olive itself give it some amazing atmosphere.