Wetlands occur on many landscapes across America. They form in low-lying areas along rivers, streams, lakes, and estuaries where they are periodically flooded (e.g., floodplains), on slopes in areas ofgroundwater discharge (e.g., seepage slopes), on broad flat interstream divides where soil drainage ispoor (e.g., flatwoods), in geographically isolated depressions where precipitation collects (e.g., potholes, playas, vernal pools, and ponds), in paludified landscapes in cold, wet climates where peat moss growsover the land (e.g., blanket bogs), and in other seasonally wet sites. Wetlands therefore may beconnected with waterbodies or surrounded by dry land. Although the latter appear to be separated fromsurface waters, many "isolated" wetlands are actually linked hydrologically to other wetlands or streamsby subsurface flow