Welcome to the Water Quality and Biological Index Maps. The Susquehanna River Basin Water Quality Index (WQI) is a tool created by Commission scientists to assess and compare water quality conditions throughout the basin. The Water Quality Index Map was developed using 19,142 samples collected by SRBC staff from 2000-2023 at 1,910 unique sites. Scoring is comprised of three category scores and an overall water quality score. All sites on the map have at least one category score, but may not have all three scores or an overall WQI score. This map displays water quality conditions for tributaries (watersheds) and sites in the Susquehanna River Basin. By using the toggle button, users may also view a water quality conditions map for only the mainsteam rivers of the Susquehanna.

The Biological Index Map was created using the Chesapeake Bay basin-wide index of biotic integrity (Chessie BIBI). More information on the Chessie BIBI can be found at: https://www.potomacriver.org/focus-areas/aquatic-life/macroinvertebrates/chessie-bibi-index-for-streams/. The Chessie BIBI uses family level macroinvertebrate metrics on small, wadeable freshwater sytems in the Chesapeake Bay watershed. Commission scientists used the Chessie BIBI to score each macroinvertebrate sample collected in the Susquehanna River basin by Commission staff or other agencies. The Biological Index Map displays biological conditions for individual sites and HUCs within the basin.

How to use the map:

• Toggle layers in the legend to change the information displayed on the map.
• Zoom to a watershed or by selecting a subbasin and then a watershed from the drop down lists.
• Zoom to a political boundary by selecting from the drop down lists.
• Click the sample locations (circles) to view additional information.