Thanks for the link to the aerial website. Why aren't there aerials from the 80's? Maybe I just missed them.
I can't make out the water slide but you can clearly see the old paddleboats docked on the river. I am not sure how long the slide was there. Probably just for a year or two in the early 80's. In the mid 80's someone opened a skateboard shop at that location.
Thank you all for the replies.