Tiny swimmers reveal Rappahannock river and stream health

A team of Old Rag Master Naturalists (ORMN), nets and magnifying glasses in hand, gathered along the banks of the Rush River in Washington last Thursday to catch and examine a wide array of swimming macro “bugs.”

Old Rag Master Naturalists collect, examine and ID several dozen macro-invertebrates at the Rush River in Washington last week. The tiny bugs give clues on the health of local streams in Rappahannock County. By John McCaslin

On hand to help capture and classify the “macro-invertebrates” were Mike and Joyce Wenger, Ed Dorsey, Barry Johnston, and Ruth Welch (Gail Swift of Washington is president of ORMN, which serves Rappahannock, Green, Madison, Culpeper, Orange and western Fauquier counties).

ORMN member Mike Wenger says of the process: “It’s a simple protocol — we take a net sample of macro-invertebrates and then ID what we have. There’s a formula that calculates stream quality based on the ratio of pollution-tolerant species and pollution-intolerant species. The more pollution-intolerant species we find relatively the healthier the stream environment is (good temperature, oxygen content, low suspended particles, chemically pure, few disease bearing microbes, etc.)

“As you would hope, our streams in Rappahannock are pretty healthy — close to the headwaters, lots of farms with good agriculture practices, good stream-side shade and buffers, etc. The Rush today, for example, scored 10 on a 12-point scale, which means ‘acceptable ecological condition.’ That’s the top category. Could be better, of course, but still good.”

The naturalists support numerous projects in both stewardship and citizen science. Stream monitoring is a citizen science project the naturalists conduct in support of the Culpeper Soil and Water Conservation District and the John Marshal SWCD, as part of the statewide program under Virginia Save our Streams.

ORMN monitors multiple streams/rivers in Rappahannock: the Rush, Thornton (North and South), Popham Run, Jordan and others. Bug monitoring is conducted quarterly on average, to allow for a good record of historic data about the health of local streams for a variety of science users. Most importantly, the team is able to discover any pollution problems pretty quickly.

About John McCaslin 477 Articles
John McCaslin is the editor of the Rappahannock News. Email him at editor@rappnews.com.