A bill to amend the definition of the term "lawful bridge" in "An Act to provide for the alteration of certain bridges over navigable waters of the United States", approved June 21, 1940 (54 Stat. 497), for the purpose of clarifying such definition.

Revises the definition of "bridge" for purposes of programs relating to the availability of Federal funds for the alteration of bridges obstructing navigation to include within such definition bridges which were lawful at the time of their construction but whose elevation has changed through no action or fault of their owners or users.