Folks, this post is by Rob Tilghman, a volunteer for StreamWatch. He explains why it matters where a stream has been.
Here’s a funny thing about rivers: Because the water is always flowing, the river you see one minute is gone the next. It’s just like that old saying: you will never, ever step into the same river twice. So when I visit Ivy Creek twice a year, I have to remind myself that it’s not the same stream from a few months ago. In fact, it’s not even the same stream from five minutes ago.
I am a volunteer for StreamWatch, a nonprofit organization that monitors the health of local streams and rivers. We do this by collecting samples of the small invertebrate animals that live under the rocks at the bottom of the stream, such as mayfly and stonefly larvae, beetles, clams, and snails. Like canaries in a coal mine, the relative numbers of these little creatures act like a warning system that tells us how impaired the stream is.
This is important because we use this same water for drinking, irrigation, and recreation, and streams are constantly moving through areas that make them prone to pollution with things like sediment (from bank erosion), chemicals, fertilizer, or anything else that might find its way into the water.
One of the things I’ve learned since joining StreamWatch is that every river or stream has its own history, which may or may not include sources of pollution. For example, Ivy Creek starts in Ivy (naturally), about 10 or 11 miles west of Charlottesville. From there, it slowly gathers water from tributaries and meanders northeastward, flowing under Highways 64 and 250, cutting across farms, wandering through residential areas, glancing off a golf course, and passing beneath Garth Road (where we collect our sample) before emptying into the South Fork Rivanna Reservoir—a primary source of water for the Charlottesville area. Like Ivy Creek, each stream we monitor has a unique history, and our sample tells us how clean that stream’s past was.
So as we visit our local rivers and streams, I think it’s important to think about the water that continually runs through them: where it is coming from, what it has seen, and where it is going. And we can be thankful for the little guys—the tiny creatures that call the water their home—for letting us know if the stream needs our help to keep it clean.