One of the simpler assignments for my current class in freshwater ecosystems was to visit the falls of the Northwest Branch (and have a picture taken to prove it).
This reach of the river is wild and urbanized at the same time. The trail is a short stumble down from a parking lot on Colesville Road. This is the site of Burnt Mills (ooh, the Internet Archive has an interesting book from 1931 about the history of the flour mill that was here). The riverborne trash is hard to overlook, and especially around the parking lot, the non-native invasive plants are pretty aggressive. Nevertheless, I found a few bits of Rattlesnake Weed (Hieracium venosum) growing around the rocks. Leta and I scrambled for a couple hundred yards downstream before turning back. I showed her an Acadian Flycatcher making sallies to a pool.
On the other side of Colesville Road, the river is held back by a dam and spillway. On this flat bit of trail, we found two Five-lined Skinks (Eumeces fasciatus): a juvenile with the familiar blue tail and a much-larger adult male with indistinguishable lines, orange-red in the head, and a truncated tail.
Leta chatted with one of the fishermen, who said that sometimes he took bream from the river. I think that we would know these as sunfish.