The Park River comes up a lot when people talk about Hartford. Some people want it to be unearthed and visibly go through Bushnell Park again. Some people like to paddle in it under the City. I think there's some kind of plan to make it in a greenway, in fact I think it's underway. There's a bike path south of Flatbush.
If you've ever been down Brookfield St or the Flatbush Ave entrance/exit ramp, you know that the concrete channel is pretty bad ass. And, it's a pretty bad ass place to ride a bike, at expedition speed or any speed. Best accessed by from Olive Street.
It's strange that there's such an effort from keeping the neighborhood away from the river.