We All Live Downstream
By C.D. Dollar
"Less than three years ago, this stream had a rocky, pebbled bottom, not the muddy bottom you see now," explained Dave Mummert, an environmental educator at the Chesapeake Bay Foundation's Clagett Farm program in Upper Marlboro. Dave and his partner, David Cola, invited me to tag along on a glorious fall day to explore the connections between the land and the streams that run through it.
The Home-schooled Anne Arundel County students sat in a semi-circle on log benches along a wooded stream. Did they remember Hurricane Floyd, Dave asked. Some of the kids nodded and a few mumbled 'yes.' Mummert then described how the Back Branch, a small tributary of the Patuxent River's Western Branch, had flooded so badly that it left massive amounts of sediment that still stained the top step of the stairs that descend to the streambed.
Dave prodded some more, trying to get the kids to make the connection between, on the one hand, a clean stream, trees and streamside buffers and, on the other, development and runoff.
"So where do you all think all that dirt, also called sediment, comes from?"
"Upstream!", someone blurted out.
"That's right. There is a housing development not far from here, and when they cleared all those trees to build the houses, it made the stream banks unstable," Dave explained. "So when a big storm comes, a lot of that dirt washes into the creek. Does that hurt the creek?"
Now the answers were coming fast: Too much sediment is bad for plants and animals that live there; it makes the water cloudy; it kills the stream. When trees are cut, the bank erodes even more.
After a safety talk and basic instruction on proper techniques to use the high-tech macroinvertebrate collection equipment (kitchen strainers and ice cube trays), the eager stream surveyors were cut loose. Teams of kids negotiated the shin-high water like biological investigators meticulously searching for minute signs of life. They peered under stones, shook debris from water-soaked leaves into the strainer and dipped under bank cuts and riffles where tiny life might hide.
The efforts of these Sherlocks of the stream revealed a variety of insects, each with a specific set of water quality and habitat requirements. They discovered that minnows like the blacknose dace live in Back Branch. This dace grows to about four inches, feeds on crustaceans, mayfly nymphs and other aquatic creatures and can tolerate fair water quality conditions.
The kids also found a crayfish and a rosyside dace, a brightly colored minnow that inhabits many upland streams in the region. This dace has a black lateral band that runs from gill plate to caudal that sets off the rosy colored ventral portion, which is in full bloom in June and July.
One of the coolest catches of the day was a tessellated darter, a small cousin of the yellow perch. Like its larger relative, the tessellated darter will travel to more saline waters, but generally is found in the fresher, clear streams with good flow, where it hides under rocks and in riffles awaiting prey. All of the 95 species of darters are perch, and they dart about in quick, furtive movements usually too quick for the human eye to follow.
Darters have exceptionally large pectoral fins that allow them to dart from spot to spot. These fins also act as stabilizers when the fish are on the bottom. Because they never suspend themselves in the water column, darters have a rudimentary swim bladder. Tessellated darters are mainly carnivores, eating small insects and zooplankton.
The insects, fishes and other macroinvertebrates we caught that day can tolerate some pollution, but Dave reported that his most recent groups have caught stoneflies and other critters that require exceptionally clean water, which speaks well for the health of Back Branch.
Just as important, these students - who perhaps are the Chesapeake's future political and community leaders, business people and teachers - learned a valuable lesson. What may appear as insignificant small trickles of water are actually important health indicators and an integral part of the Chesapeake's watershed. In addition to the 20 or so major rivers, there are hundreds of smaller creeks and streams that flow into the Chesapeake Bay.
The beauty of Back Branch hammered the axiom we all live downstream into my perception and introduced it to these young stream surveyors on that wondrous autumn day.
| Issue 48 |
Volume VII Number 48
December 2-8, 1999
New Bay Times
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