Stream Monitoring

Volunteer stream monitoring helps collect important environmental data that the County uses to monitor long-term trends of our streams.

The Office of Sustainability and Environmental Management coordinates the Volunteer Stream Monitoring Program. After participating in County-sponsored training, stream monitors wade into Arlington’s streams and report back important environmental data that we use to monitor long-term trends of our streams. The resident-collected data is also reported to the state as a part of our municipal separate storm sewer system (MS4) permit.

Macroinvertebrate Monitoring

Macroinvertebrates are small organisms that live underwater in our streams, lack a backbone, and can be seen with the naked eye. These “stream bugs” live a portion of their life cycle in the streams and depend on them for habitat and food. Some macroinvertebrates are more tolerant of stream pollution than others, which makes them good indicators of water quality. Macroinvertebrate monitoring is also helpful to compare a stream’s health before and after pollution prevention practices are enacted. If a stream has more types of pollution-sensitive bugs present than before, this indicates the stream’s health has improved.

Bacteria Monitoring

Since 2005, volunteers have been collecting water samples and testing them for E. coli on a monthly basis. The program was developed to identify areas with high bacteria levels and to help identify potential sources of bacteria. We collect the data and provide them to the Virginia Department of Environmental Quality as a section of our MS4 permit report.