This is The Quarry, in La Quinta, CA, by Tom Fazio.
The waterfall is by the 10th hole, and I'm guessing that it
gets fed by the stream on #17 (hole in top left of main
section of holes), and falls just by the 10th green, to the SE
of the 17th green.
clues include:
"Fred Flintstone" works in "Mr. Slate's" rock "quarry".
As SPDB pointed out, most viewed AOTD thread was Palm
Springs area's PGA West.
golf "hotbed" = Palm Springs area
"modest hotel chain" in town of same name = "La Quinta"
The Beatles' name before they were the Beatles, making
them sound like members here = "The Quarrymen"
Ted Robinson has built many a waterfall in southern California.
last AOTD done by Fazio = "sandy" World Woods (Pine
Barrens), which is near other "rocky" Fazio of the same name
= "Quarry" course at Black Diamond Ranch.