On the one hand, I can understand why it would need to be done, given the fact that I doubt anyone would like to deal with the legal repercussions of allowing a mass electrocution to take place every time an electric-type got overly excited.
On the other, given that I’m not very fond of amusement parks in general, I also feel that having a water park in the first place, as opposed to finding a more practical use for the land, to be rather pointless.