The Chessie BIBI measures overall condition of stream macroinvertebrate communities in the Chesapeake Bay watershed. It is used by scientists at the Chesapeake Bay Program as an indicator of stream health. The small creatures that live in a stream process organic matter, such as leaf litter, and are an important food source for amphibians, fish, and birds. They can be sensitive to pollution and stream degradation.

This map displays Chessie BIBI ratings for streams and small rivers from 2000-2017. HUC12 watersheds are colored per the rating of their average index score. In some cases, one HUC12 watershed may be split among multiple bioregions. In which case the same HUC12 may be scored differently depending on the bioregion in which it is found.

The Interstate Commission on the Potomac River Basin assembles and analyzes these data through a Chesapeake Bay Program grant. Explore more about the history of the project on ICPRB’s Chessie BIBI website. Maps with higher color contrast ratios for printing and easier visibility are available. To learn more about the bioregions, head over to the Bioregions of the Chesapeake Bay map.

Search functions: Hit the down arrow on the search bar to search by either the address or the HUC12 name or number. Please note, the search function will not work for shorter HUC numbers.