Stream Monitoring

Join A Stream Monitoring Team

Clean water is vital to healthy living for both people and wildlife. Much of the water pumped into our homes and businesses comes from the streams around us. Rainfall produces runoff that enters our aquatic ecosystem and is processed at local water facilities for human consumption. The many creeks, streams and rivers in Loudoun are also a source of nourishment for the plants and animals living around us.

How clean is the water that flows through the woods, farms, residential communities and parks of Loudoun County? One way to find out is stream monitoring.

Loudoun Wildlife Conservancy established its stream monitoring program in 1996 to compile data for submission to the Virginia Department of Environmental Quality (DEQ). The DEQ uses the data to target impaired streams for further monitoring and restoration.

What We Monitor: Our stream monitoring program involves sampling benthic macroinvertebrates, which are the insects and other small creatures that live at the bottom of streams. The type and quantity of aquatic organisms tell a good story about the quality of water in the stream.

When: Stream monitoring is conducted twice a year, in the spring and the fall. You can see a map of our monitoring sites above.

Photo by Hope Hanes

How: A certified monitor conducts a survey of a stream’s health with a team of volunteers using the Virginia Save Our Streams (SOS) monitoring protocol. The equipment such as nets, magnifying glasses, and field tables, are provided by Loudoun Wildlife Conservancy.

Team members wade into the stream and use a net to collect a sample of aquatic organisms.The organisms are then sorted, identified, and recorded on a data sheet before they are released back into the stream. Once the sampling is completed, the raw data is plugged into a series of formulas to compute a score of stream health ranging from one (unacceptable ecological condition) to twelve (acceptable).

Time Commitment: It takes a monitoring team approximately three hours to complete a survey and generate a score of stream health. Volunteers assist by transporting equipment, holding the net in the stream, placing sample aquatic organisms in collection trays, and counting the number of each type of organism collected. Volunteers are not required to have experience in stream monitoring and will be given instructions by the certified stream monitor who leads the survey.

To join a team, sign up here.