The following is the City of Rockville's State of Our Streams report outlining the health of the local streams as assessed by volunteers participating in the Save Our Streams (SOS) program. This report will be updated annually and is based on water quality sampling, benthic macroinvertebrate (small organisms) inventory and habitat assessment. SOS volunteers collect this data in the spring and fall.
Rockville's SOS program was developed to engage the community in environmental stewardship through monitoring the quality of city streams. SOS volunteers work the City's Environmental Management Division to assist in monitoring each of Rockville's three watersheds: Cabin John, Rock Creek and Watts Branch. The City provides training for all SOS volunteers to teach data collection in streams.
Rockville has a large network of streams that twist and wind through the City's neighborhoods and parks. Beyond providing recreational value, these water bodies provide important services to Rockville residents as well as local wildlife.
Millions of people receive their water from the Potomac River, including Rockville residents. All of the streams in the City eventually flow into the Potomac River. The more polluted streams are, the more difficult it is to process the water from the river, so that it is safe for use. Pollution of streams can come from many places. In this area, the most common way is from rainwater runoff. All of the rainwater that enters the storm drains in Rockville flows directly into streams picking up pollution from roofs, driveways, roads and lawns (fertilizer, pesticides, animal waste, chemicals and/or sediment) along the way.
Rockville's streams also provide habitat for local wildlife and aquatic organisms, like bugs and fish. The aquatic organisms in Rockville's streams are part of a complex food chain where they serve as a source of food for larger animals downstream – a food chain leading all the way to the Chesapeake Bay. Pollution, poor habitat quality and limited food resources can negatively impact the organisms that live in our streams. This will ultimately have a negative impact on the organisms living downstream in the river and the bay.
In the stream, SOS volunteers take water quality samples to evaluate things like pH, temperature and dissolved oxygen. SOS volunteers also identify benthic macroinvertebrates (BMIs) like crayfish, snails, worms and many different kinds of insect. Since certain types of BMIs cannot live in polluted or stressed environments, the presence or absence of certain BMIs can be an indicator of stream health.
SOS team members are also trained to conduct habitat assessments during monitoring. During an assessment, team members look for favorable habitat conditions, including places for BMIs to live like submerged logs and areas with a variety of stones, ranging from large to small. The assessment also looks at vegetation in and out of the stream, which serves as an important food source for many insects.
Using the data collected by the SOS volunteers, including the water quality data, BMI survey and habitat assessment, we can establish a general sense of the health of the stream. The data collected in the field is imported into a computer program designed to help rate stream health. Streams can be rated as optimal, suboptimal, marginal or poor.
Currently, Rockville streams rate from suboptimal to poor. As the SOS Program matures and more data is collected, we can look at trends or changes in the data over time. This knowledge may help influence future projects to positively impact and prevent future damage to watersheds.
For a more detailed look into the data collected by the SOS volunteers, you can read the full State of Our Streams report. If you are interested in learning more about the SOS program or are interested in becoming a SOS volunteer, please contact the City of Rockville's Environmental Management Division at 240-314-8870 or environment@rockvillemd.gov. 
Map of stream monitoring sites; color of site marker indicates stream integrity score.
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