White Water was Garland's first water park. It was open from 1982 until about 1993.
It's kind of surprising how little about its history is online. Here's what I was able to piece together:
In 1982, White Water opened on the grounds of what is now Carmax.
(A little tidbit that I found interesting is that they re-routed Long Branch Creek around the backside of the parking lot. It still flows in the concrete ditch around the North and East sides of this parking lot.)
Around 1986, Wet 'n Wild, which had multiple locations, purchased the park and changed the name.
In or around 1991, Six Flags purchased Wet 'n Wild and all of its water parks.
By 1993, Six Flags apparently decided that Wet 'n Wild, Garland was not earning its keep. It has, however, been suggested that they found it was taking too much business away from their Arlington location. Either way, the result was the same and that was that Garland's only water park was closed. (Ten years later, Hawaiian Falls opened in North Garland.)
The tract of land that contained White Water and Wet 'n Wild was bisected by Millay Blvd. sometime before Carmax moved here. This all but stranded this back section of the parking lot. It has no enterance and is six to eight feet below the level of the road and the tract where Carmax resides. Wet 'n Wild's creator was George Millay, who also created the first Sea World. He has been named "Father of the Waterpark" by the World Waterpark Association. I haven't found any records to verify the naming of this street, but it seems quite likely that it is named after him.
Just a little update. I spoke with the manager at Carmax about the No Trespassing signs. He said they've had some homeless in the area and put up the signs in an effort to keep them from congregating there. He said "this geocaching thing" is not an issue.
Congratulations to BriarBoy and GeoMojoGirl for the FTF!!