Ms. Carol Ann Siciliano of the U.S. Environmental Protection Agency explains to senior Emily Sabbatini how small creeks and streams in the City of Falls Church affect the Four Mile Run water system. Ms. Siciliano visited Dr. Mecca’s block six Biology II class as part of a unit on different biospheres. She showed various pictures of the smaller bodies of water that help manage water runoff throughout the city. (Photo by Andy Pribulka)