Water Quality Monitoring
NNWB supports three different stream water quality monitoring programs - all are welcome to voluntee
1. Anacostia Riverkeeper's (ARK) water quality testing program runs through the spring and summer. NNWB volunteers conduct testing at sites in Montgomery and Prince George's Counties. Volunteers are needed for sites in Montgomery and Prince George's Counties. This program measures e coli (bacteria), turbidity (cloudiness, such as from sediment), pH, dissolved oxygen (fish and zooplankton need this to breathe), temperature and specific conductivity. ARK posts the results on a map here.
2. NNWB volunteers test water for salt (via chloride levels) through the Izaak Walton League's Salt Watch program. Salt pollution is unfortunately common in cold-weather months when jurisdictions and residents use chloride-based ice melt. We test the water year round and after each snow or ice event. See data from our sites here. Contact us to get involved on NNWB's sites or establish a new test site near you.
3. We participate in Nature Forward's macroinvertebrate program (see photos and a description below). See how to participate here.
ARK Water Quality Testing
Collecting samples for bacteria and turbidity
Measuring air temperature
Measuring water temperature
Labeling a sample. The bacteria sample must be analyzed within 5 hours, so the label must have time
Labeling a sample. The bacteria sample must be analyzed within 5 hours, so the label must have time
Labeling a sample. The bacteria sample must be analyzed within 5 hours, so the label must have time
Labeling a sample. The bacteria sample must be analyzed within 5 hours, so the label must have time
recording samples on the datasheet.
Labeling a sample. The bacteria sample must be analyzed within 5 hours, so the label must have time
recording samples on the datasheet.
measuring pH.
Labeling a sample. The bacteria sample must be analyzed within 5 hours, so the label must have time
recording samples on the datasheet.
Macroinvertebrate Monitoring
Join Neighbors of the Northwest branch in Changing Lives
We partner with Nature Forward at to monitor the NWB at Adelphi Mill every spring, summer, and fall. The macroinvertebrate species living in the water provide biological indicators of ecosystem health and water quality. Below are the benthic macroinvertebrates that we found on 10/19/25. Based on these findings, our IBI (Index of Biological Integrity) Score was 2.71, indicating FAIR water quality:
- planarians (Family Dugesiidae)
- midge fly larva (Family Chironomidae)
- black fly larvae (Family Simuliidae)
- common netspinner caddisfly larvae (Family Hydropsychidae)
- fingernet caddisfly larvae (Family Philopotamidae)
- small minnow mayfly larvae (Family Baetidae)
- flatheaded mayfly larvae (Family Heptageniidae)
- damselfly larva (Family Coenagrionidae)
- dobsonfly larvae (Family Corydalidae. “Hellgrammite”)
- water striders (Family Gerridae)
- *possibly* an Asian clam (Family Corbiculidae) was collected, but we didn’t find it in the sampling tray.
You can find data for all sites here.
Macroinvertebrate Monitoring
Monitoring Event, October 2025
Monitoring Event, October 2025
Monitoring Event, October 2025
Getting set up
Monitoring Event, October 2025
Monitoring Event, October 2025
The Collecting
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mayflies stoneflies and caddisflies larvae indicate a healthy stream,
Salt Watch
Info coming soon
