We have the L.A. river, which I would have never called a river growing up. After the flood of 1914 is was channelized/paved for flood control. So all that cement for years was just a canvas for graffiti artists, until the last several years where they've let the parts of river to return to a more natural state with brush growing, fish returned (not native species), people kayak in sections now. They don't call it a restoration, but rather habitat enhancement. But it's more of a river now. We also have the San Gabriel river which you can travel on the bike path from the mountains about 20 miles to the beach.
We also have a natural creek called the Arroyo Seco coming down from the mountains and going through Pasadena where it's also channelized and turns into a "wash." But the section in the foothills (near JPL) is beautiful. I sometimes ride my bike from my house to the creek/woods during my lunch break. The best part is that most people around here either don't know about it or never go there.
But when I want to go stream fishing for trout I drive up to the Eastern Sierras. Everything's nicer at 10,000 ft elevation.