Wetlands are often found at the interface between dry terrestrial ecosystems such as upland forests, grasslands, and cropland, and permanently wet aquatic ecosystems such as rivers, lakes, bays, estuaries, and oceans. A wide variety of wetlands exist across the country because of differences in climate, soils, topography, hydrology, vegetation, and other factors. Inland wetlands are most common on floodplains along rivers and streams in isolated depressions surrounded by dry land, and along the margins of lakes and ponds.
Wetlands are the primary habitat for many species of plants and animals.
Wetlands provide many benefits including food and habitat for fish and wildlife, water quality improvement, flood protection, groundwater exchange, and shoreline erosion control. Wetlands help protect water quality by intercepting pollutants in surface water runoff before they reach surface water bodies, removing or retaining nutrients and sediment, and processing chemical and organic waste. As water moves slowly through a wetland, sediment and pollutants settle out, and plant roots trap sediment. Pollutants are metabolized and nutrients such as nitrogen and phosphorus are removed. The preceding links are provided as references only.