Casco Bay was designated an "estuary of national significance" by the U.S. EPA in 1990 in part because of its relatively pristine nature but, also because of the increasing pressure on its water quality and habitats from human activities. For generations, Casco Bay and the waters that feed into it have supported industries such as shipping, commercial fishing, and tourism and have also, made the area a popular destination for living, working, and recreating. As a result of these varied uses, the Bay and its watershed face a myriad of environmental issues arising both directly from human activities such as sewage disposal and indirectly from population growth, suburban sprawl and other pressures.

While the health of the Bay has generally improved over the years, specific problems relating to pollution and habitat loss remain. More recent concerns have also surfaced, including the arrival of new marine invasive species and "emerging" contaminants from pharmaceuticals and personal care products.

The Casco Bay Plan, which directs the work of the Casco Bay Estuary Partnership, focuses on five key areas of watershed protection: stormwater management, shellfish and swimming area protection, toxic pollution reduction, habitat conservation, and monitoring and stewardship. To learn more about these environmental issues in the Bay and its watershed, click on the links below: 

Stormwater