It is based on a protocol known as Streamwalk developed by the EPA Region 10 Office in Seattle, Washington, and is widely used by volunteers throughout the Pacific Northwest. Monitors evaluate the macroinvertebrate community structure by sorting specimens into three general sensitivity categories. In addition, volunteers characterize habitat by conducting a modified Stream Habitat Walk. This tier is based on a protocol developed by the Ohio Department of Natural Resources and adapted by the Izaak Walton League of America. It has been used by volunteer monitors nationwide, including programs in Ohio, Tennessee, Georgia, Virginia, Kentucky, Illinois, and West Virginia.
Volunteers undergo formal training and conduct quality-controlled sampling and analysis.
Analytical techniques are subsequently applied to the data to draw conclusions about the biological health of the sampled site. This rigorous biosurvey approach results in data that can yield information on subtle stream impacts and trends. Based primarily on EPA's Rapid Bioassessment Protocols, this approach has been adapted by Mary-land Save Our Streams, the River Watch Network and other groups. We have modified the approaches used by other groups to add to their capabilities or to make them more generally applicable to all U.S. streams. Individual programs might choose to start with the simplest, least resource-intensive approach and work their way toward increasing complexity as resources, expertise, and volunteer interest allow.