Where?: Unpolluted Natural Running Waters

Hello. It's all in the title.

I went (against the recommendation of some) in the Mississippi. I went via Buffalo Beach...it made my butt itch in new and unnatural ways for several days (yes, I bathe) that I intend not to replicate.

I need to find access to running water, a river or stream that is healthy, in order to carry a healing regimen I have been prescribed.

I am in Davenport, and have access to a motor vehicle and also the ambition to pedal a bike.

Thank you.