You can read the nomination form that the city prepared to get Highland Park onto the National Register of Historic Places in its entirety at archive.org. It’s a fascinating look at the park in a darker time, when rusty playground equipment poked through weeds and the paint peeled off the standpipe.
It’s also perhaps the most detailed history of the park and the standpipe I’ve found yet, and since it was prepared by the city office in charge of such things I think it’s probably the most accurate version of things we’re likely to find online. Enjoy!