The city deals with the Montana Municipal Insurance Authority and they have their own schedule of risk. So it is up to MMIA on that point. And those releases only work IF you truly are not at fault. You don't maintain your property and you can still be sued. Ask a ski hill. If the lift breaks, they pay.
The other problem is those big fiberglass slides do not last a long time, especially in our climate. Like the frog at Wibaux Park, it would have to be dismantled every fall and set up again in the spring and still probably only last a few years.
Plus, with weight and structure issues, it couldn't be set up a easily as the frog.
I am sure once the dike is built, the water and sewer plants are brought up to new standards, all the old city water, sanitary sewer and storm sewer lines are replaced, Denton Field is repaired, the fountain at Wibaux Park is restored, all the streets are resurfaced. . . .