I have heard 5 thousand, but may be wrong on that.
I have wondered why no one came up with a portable Chute the Chute ride, you know the big boats that make the big splash.
You would only need one drop that could be directed back to the center of that huge pool and with the plastic shields I think keep most of the water in there. Seems that would make more money than the Flumes and still be about the same size in terms of footprint and loads.