Urban Swimming Cities/Towns?

Hello! I've lived in Austin TX and loved Barton Springs, kayaking or SUP'ing in Lady Bird Lake/Town Lake, and sitting in the river in the greenbelt. There were many places you could get in the water within 15-20 minutes of downtown. I'm interested in moving someplace with similar urban water access, especially if it is reasonable year round (not iced over). Seeing those european towns where people literally float home from work has me *dreaming*. Any ideas?

I head maybe Portland, OR. I also saw potentially Richmond, VA. I looked up a TON of cities with rivers but many were said to be unsafe/unclean.