A watershed is an area in which water, sediments, and dissolved materials drain to a common outlet, such as a river, lake, bay or ocean. An estuary is an area where freshwater empties into and mixes with saltwater. The shorelines within estuaries can be vegetated with many types of plants, including mangroves and sea grass beds. These areas are important breeding grounds for a variety of fish, shellfish, and shorebirds. The Chesapeake Bay, Galveston Bay, and San Francisco Bay are all examples of estuarine systems.
Dune vegetation provides nesting areas for several kinds of birds and animals.
The types of species found on a beach are determined by the type of beach. In the harsher climate of New England, beaches are dominated by a few species of hardy grasses and bushes that can withstand strong winds, cold winters, and intense summer sun. Stretches of beach along the coasts of the United States provide numerous recreational opportunities for millions of people. Boating, fishing, swimming, walking, beachcombing, bird-watching, and sunbathing are among the numerous activities enjoyed by beachgoers. The aesthetic aspects of a beach system provide additional benefits, even inspiring works of art and literature.