Wetlands are areas where land and water meet. They are transitional areas between aquatic and upland plant and animal communities, and often have some of the qualities of both. Wetlands also occur where the groundwater occurs near or at the surface, saturating the soil and the root zone of the plants that grow there. Freshwater wetlands commonly include marshes, swamps, bogs, and fens.
Riparian wetlands occur in the floodplain adjacent to streams and rivers.
Finally, wetlands can occur where surface water is trapped in shallow depressions by soil that will not allow the water to seep downwards. These are called depressional or flat wetlands and are common on clay soils in the Lake Plains of western New York. When scientists look at wetlands, they usually look at a few key characteristics. The most relevant one is water. Water, or the wetland's hydrology, is why the wetland exists.