OK, you asked for a comments in the next posting. The drain itself is just a drain, nothing more or less. The curve, which your title suggests was your focus, doesn't stand out against the drain. What you need is something that makes someone think about something. (OK, a roadway engineer might spend his time thinking about storm drains, but most of us don't.) Human interest is always good, so an identifiable item flowing down the storm drain in rain, or even a broken toy under the leaves. If you're willing to stag the picture rather than insisting on "found" pictures then you can just go buy a cheap doll at K-Mart, rip one of the arms off, and place it. Or a lost wallet.
But the trick to getting viewer reaction is to get viewer self identification. Either, "I remember something like this" or "Man they must like/hate that."
MB