How Healthy Is Your Stream? Find Out As A Volunteer Stream Monitor

(Conservation Currents, Northern Virginia Soil and Water Conservation District)

By Matthew Monteverde, NVSWCD Intern

 Every year hundreds of streams in the United States are contaminated by pollutants that degrade their overall health. What most people do not realize is that a large portion of this stream degradation is attributed to us. After a rainfall event, paved areas and rooftops create large volumes of surface runoff that pick up contaminants on our roads and lawns (such as oil and fertilizer) before flowing into storm drains which channel the polluted runoff directly to our streams. Fairfax County has 30 major stream watersheds, all of which feed into the Potomac River and Chesapeake Bay. Both the increased runoff volume as well as the contaminants can have very adverse effects on our aquatic ecosystems, and in particular, on our populations of benthic macroinvertebrates.

What are macroinvertebrates and why are they so important to the health of our streams? Benthic macroinvertebrates are small but visible aquatic animals without a backbone that live at the bottom of streams for at least some portion of their lives. They can be found under logs, sediment, rocks and aquatic vegetation.



Often, when we think about determining water quality, we imagine chemical tests such as pH, dissolved oxygen or nitrate testing. Although these give us a numerical value as to the quality of our water, the numbers are subject to high variability within the stream. A less expensive, more efficient method involves using biological monitoring to evaluate the abundance and diversity of benthic macroinvertebrates found in the stream to assess habitat quality.


Currently only 36% of the rivers in the US are monitored by the government. We know very little about the condition of many of the streams and rivers, even in our own backyards, and it is up to volunteers to do additional monitoring to protect the health of our streams.


Stream monitoring is a fun, easy way to determine if your local stream has been impacted by pollution sources. To get involved and find out about upcoming events, contact Dan at or 703-324-1422, TTY 711.

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