Stream bug monitoring
King County, Washington

Stream bugs are also called "benthic macroinvertebrates." Macroinvertebrates are animals that you can see with the naked eye that don't have backbones. Some examples include insects, crustaceans, worms, snails, and clams. The term "benthic" refers to bottom dwelling animals. So benthic macroinvertebrates live in and on the bottom of the streambed and other substrates such as logs and plants in the stream channel.

King County monitors stream health by collecting samples of benthic macroinvertebrates from selected streams. Scientists use a score-card system to rank the health of the streams. The scores are based on what type of bugs are living in the stream and the number of different kinds of stream bugs present. By using this scoring system, we can compare very different streams to each other and rank their ecological health.

In this web site you can find general information about benthic macroinvertebrates, why they are important in streams, how King County uses them as stream health indicators, and information on county streams that are being monitored. Next time you are walking near your neighborhood stream (after reading Your Guide to Visiting Watersheds), carefully pick up a rock. You might be surprised at what you find!

Also, the Puget Sound Stream Benthos web site was developed by a group of agencies interested in monitoring the health of streams in the Pacific Northwest. The City of Seattle, King County, Pierce County, and Snohomish County worked collaboratively to create a database system that allows sharing of benthic macroinvertebrate data among many organizations and provides tools for calculating metrics and indices. The site is used to store and analyze data from ongoing macroinvertebrate sampling programs.

View presentations on stream bugs given by King County staff on the Science Seminar Web site.

For questions about information on this page, please contact Deborah Lester, Risk Assessment Lead, or Jo Wilhelm, Environmental Scientist.