Stream Health

Maryland’s Stronghold Watersheds

In its 17 years of assessing the health of Maryland’s streams, the Maryland Biological Stream Survey has identified those watersheds around the State that are most important for the protection of Maryland’s aquatic biodiversity. Known as Maryland’s “Stronghold Watersheds”, these locations are the places where rare, threatened, or endangered species of fish, amphibians, reptiles, or mussels have the highest numbers.

Map of Maryland's Stronghold Watersheds

Most of these species used to have greater abundance and distribution throughout the State, but now are holding out in these limited areas. Generally, these species are the most sensitive to environmental degradation. A small change in watershed or stream health can permanently eliminate one or more of these sensitive species. As a result, maintaining the health of these watersheds is of critical importance if we are to sustain these species and the vital ecosystem services they provide.