The place where they'll get wet is the playground behind Shamu stadium. There is a tube crawl, in a pool of water. It's not that big, kinda like the ones you find at McDonalds or BurgerKing, but this one is wet. There is also a ship in the middle of a pool with water blasters.
The cargo net crawl will keep them busy. This is the one where you climb up cargo nets, crawl thru tubes, and sit on tire swings. You're 3 stories in the air, really amazing. For the 3 year old, there is a rope climb at the bottom where they grab a rope, climb up a padded pyramid, and slide back down.
There are tables under the cargo net crawl. The parents hang out while the kids play. Bring a good book to read, because the kids will want to stay here for hours. Take turns with your spouse getting food/drinks/beers. Or one of you could go on the thrill rides (JTA/Kraken) while one stays and watches the kids. Only thing is, these rides are on the other side of the park, so it's a long walk, but it can be done.