The Cowardin system is - according to the USDA terminology - "a classification system of wetlands and deepwater habitats of the United States, officially adopted by the U.S. Fish and Wildlife Service (FWS) used to develop wetland data bases. The system was developed by Lewis M. Cowardin of the U.S. Fish and Wildlife Service and others. The five major systems are Estuarine, Lacustrine, Marine, Palustrine, and Riverine."