Hi Wendy:-)
I live in Mexico....and I've been there!!

Hope this helps:-)
terry

Hi again Wendy:-)

Though I still think my original answer is correct, if I may, I'll change it to "water roller coaster" [Alfpach's fault:-))))].

I did some Internet research to corroborate my first answer, and this is what I got:

See:

http://www.excite.com/travel/tourist_attractions/amusement_p...

"SeaWorld Florida - Ride a water roller coaster or interact with dolphins at this marine-animal theme park outside of Orlando. Find admission details".

Seeya:-))
terry

This is one word, and it is not synonymous with flume, as in the American amusement park industry a flume is another thing, where riders board some other thing, like a hollow log, and ride it on a faux river that travels in a circuit. Your term would be simply 'waterslide', and it is a long slide that a person rides down with a mat, or often with nothing at all, into a pool of water below.

In Mexico they call them 'acquatic mountain', but this is not so in the united states. As you say--en una pista de agua quese recorre a bordo de balsas inflables--pista de agua is the translation for waterslide, and that's what we call them in English. In Mexico they call them acquatic mountains in the same way they call rollercoasters 'Russian Mountains'--they were first built in Russia, but they did not have tracks like the later US versions. Trust me on this; this is one of my specialties.