Wetlands, with a variety of physical characteristics, are found throughout the country. They are known in different regions as swamps, marshes, fens, potholes, playa lakes, or bogs. Although these places can differ greatly, they all have distinctive plant and animal assemblages because of the wetness of the soil. Some wetland areas may be continuously inundated by water, while other areas may not be flooded at all. In coastal areas, flooding may occur on a daily basis as tides rise and fall. Functional values, both ecological and economic, at each wetland depend on its location, size, and relationship to adjacent land and water areas. Many of these values have been recognized only recently. Historically, many federal programs encouraged wetlands to be drained or altered because they were seen as having little value as wetlands. Wetlands issues revolve around disparate scientific and programmatic questions, and conflicting views of the role of government where private property is involved. Scientific questions include how to define wetlands, the current rate and pattern of wetland declines and losses, and the importance of these physical changes.