The stream

Oct. 31 9:30AM

I've been wanting to focus on the stream for a while now but it's getting a little late in the season. It's the middle of autumn with seasonal temperatures. The leaves are changing and falling. I don't readily see much life in the stream, or more likely, my impatient and untrained eyes just aren't catching any of the life that is there. There's a small school of fish in a pool at the confluence by the mandala, most are <2" but 2-3 are approaching 6". A moment later, they're all gone, disappeared into the shadows or into other waters. During one of my visits in the summer, I counted over a dozen crayfish in this same spot. My intro biology lab explored the diversity of the stream at the start of the semester, maybe 400M upstream. I don't fully trust their identification skills but they found a bunch of invertebrates. Then we used their captures to consider the health of the stream. Because different species have different tolerances to pollution and water quality, we can use these aquatic communities to gauge stream quality, what's called biomonitoring. The results from our class concluded that Gwynns Falls here on campus ranges from slightly to severely impacted depending on which metric is used. It isn't surprising that water quality here isn't pristine. We're downstream from some substantial suburban development consisting of housing, retail, and even industrial activity. A walk along any stretch of the stream shows evidence of this impact with ample garbage strewn about.

The stream here is very dynamic, more so than I first thought. Its path has shifted since I started this project last winter. My mandala is bordered on two sides by Gwynns Falls and a smaller tributary. The small confluence pool has gotten deeper. The tributary's path to the main branch has cut across the gravel bed rather than following the edge. The gravel bed in the middle of the stream bed has been built up a bit and the channels deepened. There's been increased bank erosion, slowly cutting away bits of forest, exposing tree roots. Much of these changes are due to the substantial flooding that occurred periodically since summer. We're on pace for the wettest year in recorded history for the area, the last 140 years or so. There were two weeks that particularly drove this pattern, during which the stream bank overflowed and the mandala and surrounding forest were beneath flowing water. There are impressive debris dams across the stream, most of which contain disgusting amounts of plastic water bottles, toys, car tires and parts, sports equipment, etc. Of course this is just one stop on the stream's journey. Gwynns Falls is one of the major watersheds in the area, responsible for draining these western suburbs and western Baltimore, dumping into Patapsco River and then Baltimore Harbor. I'm confident that the water quality steadily declines downstream as human impact steadily increases.

We may be near peak autumn colors and leaf fall, and there's a decent amount of leaves in or along the stream. I suspect that the food we in the stream is largely dependent on the allochthonous inputs, leaves that represent the food web's energy source. There isn't much plant life here, some algae but that's about it. And that has me wondering about the timing of these inputs. The vast majority of these inputs occur in fall as biotic activity is diminishing for the season. What do these inputs look like over the year? Do a sufficient amount of leaves persist into next season?

Lastly, this is very serene here. If it weren't for the noise pollution, I'd say this would be an ideal spot to set up camp. The bubbling brook, the colorful tall trees, the birds chirping and flittering about. It's quite idealic.