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Loudoun Wildlife ConservancyLoudoun Wildlife Conservancy
  • About Us
    • Mission & Vision
    • Board of Directors
    • Staff
    • Volunteer Program Coordinators
    • Our Partners
    • Contributing Photographers
  • Events
  • Our Work
    • Education
      • Programs and Field Trips
      • Youth and Family Program
      • Peterson Young Naturalist Program
      • Habitat Herald
      • Eagle Cam at Dulles Wetlands
    • Citizen Science
      • Stream Monitoring
      • Butterfly Count
      • Amphibian Monitoring
      • Bluebird Monitoring
      • Bird Counts
    • Habitat Conservation
      • Habitat Restoration in the Community
      • Protecting Pollinators
      • Wildlife Sanctuary Program
      • Plant NoVA Natives
      • Native Plant Sales
      • Greening Your Neighborhood
    • Conservation Advocacy
      • Current Campaigns
      • Dark Skies
      • Past Campaigns
    • JK Black Oak Wildlife Sanctuary
      • Overview of JK Black Oak
      • What’s Happening
      • Vernal Pools
      • Flora and Fauna
      • Volunteers at Work
      • Support the Sanctuary
  • Store
  • Resources
  • Volunteer
    • Volunteer opportunities
    • Volunteer application
    • Waiver form
    • Volunteer hours
  • Contact
  • Stay Informed!
  • Donate

Benthic Macroinvertebrate Surveys

Benthic Macroinvertebrate Surveys

Loudoun Wildlife has been conducting benthic macroinvertebrate surveys around the county since 1996. We submit our survey data to Virginia Save Our Streams (VA SOS), a program administered by the Izaak Walton League of America (IWLA). VA SOS then approves and aggregates the data for the state and submits it to the Virginia Department of Environmental Quality, which in turn uses the information to identify impaired streams to target for further monitoring, habitat restoration and pollution control efforts.

Loudoun Wildlife is a partner with IWLA’s Clean Water Hub, where all our biological and chemical data are accessible by individual sites. If you are interested in viewing this data, click on “Explore the Map” and type in “Loudoun Wildlife Conservancy” in the search by organization field.

You can learn more about our sites and view data from our active survey sites by clicking on the site names beneath the map near the bottom of the page.

Stream Monitoring Teams

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.

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.

Learn More:  View our video series and sign up for our quarterly email newsletter, The Monitor, or view it online.

To join a team, contact Amy Ulland at aulland@loudounwildlife.org.

Where We Monitor

We currently have 28 active sites (JK Black Oak Wildlife Sanctuary has two) all over the county. Click on a site name beneath the map to learn more about, and see the data for, that site.

Stream monitoring sites as of 9-18-24

Click on map to enlarge.

Hellgrammite

Hellgrammite.
Photo by Amie Ware


Water Penny

Water Penny.
Photo by Amie Ware


Stonefly

Stonefly.
Photo by Amy Ulland

1. Black Branch
2. Sweet Run Tributary
3. Tuscarora Creek, W&OD
4. South Fork Catoctin Creek
5. North Fork Catoctin, Hillsboro
6. Town Branch
7. Beaverdam Run
8. Goose Creek
9. JK Black Oak Wildlife Sanctuary, Upstream
9. JK Black Oak Wildlife Sanctuary, Downstream

10. Crooked Run
11. Limestone Branch Tributary
12. Tuscarora Creek, IWL Park
13. Tuscarora Creek, Westpark
14. N Fork Catoctin Creek, Upstream
15. N Fork Catoctin Creek, Downstream
16. Dry Mill Branch
17. Broad Run, Willowsford
18. Unnamed Tributary, Round Hill
19. Piney Run

20. Beaverdam Run Tributary
21. Catoctin Creek
22. Dry Mill Branch, Westpark
23. Town Branch, Harrison Street
24. Russell Branch
25. Balls Run, Phillips Farm
26. Cattail Branch
27. Unnamed Tributary, Horsepen Run

Things You Can Do for Our Local Streams

Keep Streams Healthy

Understand How Humans Affect Streams

Floodplains, Better Left Natural

Forests: The Last Defense

Our Work

  • DISCOVER: Education
    • Programs and Field Trips
    • Youth and Family Program
    • Peterson Young Naturalist Program
    • Habitat Herald
    • Eagle Cam at Dulles Wetlands
  • EXPLORE: Citizen Science
    • Stream Monitoring
      • Benthic Macroinvertebrate Surveys
      • Clean Drinking Water for Lucketts
      • Salt Watch
    • Butterfly Count
    • Amphibian and Reptile Monitoring
    • Bluebird Trails/Nestbox Monitoring
    • Bird Counts:
      • Christmas Bird Count
      • Celebrate Birds/Birdathon
      • Young Birding Program
      • Bird Atlas
  • RESTORE: Habitat Conservation
    • Habitat Restoration In the Community
    • Protecting Pollinators
      • Native Bees
      • Bringing Back the Monarch
    • Wildlife Sanctuary Program
    • Plant NoVA Natives
    • Native Plant Sales
    • Greening Your Neighborhood
  • PROTECT: Conservation Advocacy
    • Current Campaigns
    • Dark Skies
    • Past Campaigns
  • PRESERVE: JK Black Oak Wildlife Sanctuary
    • Overview of JK Black Oak
    • What’s Happening
    • Vernal Pools
    • Flora and Fauna
    • Volunteers at Work
    • Support the Sanctuary
LOUDOUN'S GREAT PLACES

Citizen Science News

  • Celebrate Birds, Go Birding 2025: Bird Walks and The Big Sit To celebrate spring migration and World Migratory Bird Day, Loudoun...
    Read More
  • Loudoun Bluebird Notes Loudoun Bluebird Notes is published several times a year for...
    Read More
  • Loudoun Bluebird Trail Data Click on the links below to view the data collected...
    Read More

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