1970

• Congress creates the Environmental Protection Agency.

1971

• The D.C. Council prohibits water contact sports in the Potomac, Rock Creek, and the Anacostia River. Urban sediment is a major concern.

1972

• Congress, establishing a national goal of "swimmable-fishable" waters, passes the Federal Water Pollution Control Act Amendments (Clean Water Act, or CWA). Visit U.S. Environmental Protection Agency's web site for more information on the Clean Water Act.

1973

• Algae blooms in the Potomac River are beginning to diminish

1976

• Largemouth bass reappear in waters in the Washington, D.C. area.
• To the delight of pleasure-boaters and conservationists, there is a noticeable lack of blue-green algae mats that had covered the upper estuary of the Potomac a decade earlier.