Seems as good a thread as any to ask a question I've been trying to get some info on recently.
Encanto Golf Course (sometimes called Encanto Park) is a City of Phoenix muni originally designed by William P Bell in the 30s. Historic aerials going back to the 50s show an island green (probably the 5th hole at that time, but not sure). However, I haven't been able to dig up anything to indicate whether the island green in the 50s was an original part of Bell's course.
The island green was eliminated sometimes in the 80s.