The story I heard while working at Disney World, was that one of Walt Disney’s daughters husband wanted to go surfing in front of the Polynesian. He had them crank up the wave making machine to make bigger waves. This caused hydraulic lines to blow and hydraulic fluid to go into the water. The EPA shut the lake down, and it was never repaired, and has not worked since.
I used to swim in the lake daily after work to cool off and relax.
There was also an area of land that is between the monorail station going toward the contemporary that was to have a Mediterranean resort built. But obviously that never happened.