Md. Code Ann., Nat. Res. § 8-1303

The appropriate county governing body of Howard, Montgomery, Prince George’s, Anne Arundel, Calvert, Charles, and St. Mary’s counties or the duly designated agencies of the appropriate county governing body shall have the jurisdiction, power, and authority to define and create the Patuxent River Watershed in their respective counties. Each shall act cooperatively with the Department and local, county, State, and federal governments to protect areas subject to sediment or erosion damage and prevent encroachment by rapid growth and spread of urban development by creating a program of flood prevention and conservation.