Wetlands Wetland, geographic area with characteristics of both dry land and water. Wetlands typically occur in low-lying areas at the edges of lakes, ponds, streams, and rivers, or in coastal areas protected from waves. They are found in a variety of climates on every continent except Antarctica. The Role of Wetlands in an Ecosystem Wetlands prevent flooding by holding water much like a sponge. By doing so, wetlands help keep river levels normal and filter and purify the surface water.
Wetlands accept water during storms and whenever water levels are high.
When water levels are low, wetlands slowly release water. They are areas where land and water meet and are wet for an ecologically significant part of the year. Wetlands may be temporally flooded each day as with tidal marshes, or be filled seasonally with water from melting snow. Top of Page Classification of Wetlands Classification of Wetlands Wetlands vary greatly in their genesis, geographical location, water regime, chemistry, and plant communities. To permit description of the wetlands in Canada, a classification system was developed by the National Wetlands Working Group in 1988.