The first-described park is actually called Pattaya Park, and is located at the foot of Thapraya Soi 12, also known as Soi Pattaya Park or the Russian Soi (although not many Russians there any more). BF and I use the Park on Wednesdays when the beach concessionaires are closed. The entrance fee is 100 THB, and is the same for both Thais and farang. It's old, not particularly well maintained, but is a pleasant place to spend a Wednesday. The water is a circular, moving waterway nearly a meter deep. It's clean and pleasant and there are usually a number of nubile youths playing in it to provide visual action while you're cooling off in the water. There is a restroom and a separate changing room which includes a shower. There are several seating areas, only one of which has decent relaxing chairs. There are canvas-sling chairs available, but I can't stand to sit in them. The park has other features, some of which still are in operation. There are several water slides that are fun to use.
I'm told that the other water parks described in the post are very expensive, although like the author, I haven't been in any of them.