Island Park feels more like a campground, with a playground in the middle, I don’t think I’d go back just to play. The river running nearby has a metal bridge going over and you can see the dam.
Kuehn Conservation Area is a large park with very diverse plants and habitats, with extensive trails. At the front of the park there is a large tipi, which is used for the annual Prairie Awakening Celebration. It’s easy to feel like you’re in the middle of nowhere in this park, with lots to explore and a bird blind to check out.
Pammel Park has a lot to offer, with historic sights to see, extensive trails, a nature center, and the only highway tunnel in Iowa. Middle River runs through the park, with a ford providing perfect splashing for kids. There is easy creek splashing access here, you can see more specific details about how to get into the water in this post.
Clanton Creek Natural Resource Area is a large wildlife area with no interior roads, with several different habitats and pedestrian traffic only.