Wetlands are known by many names: marshes, swamps, bogs, wet meadows, seasonal ponds and wet woodlands. For scientists, wetlands are areas that are periodically flooded or saturated enough to affect plant growth and soils. Wetlands receive water from tides, rain, surface water runoff and groundwater discharge. Some, such as tidal marshes and floodplain wetlands, are flooded all year; others are never flooded but the water table is at or near the surface for a few months, keeping soils wet.
Tidal and nontidal wetlands are natural filters that absorb water runoff. They maintain water quality by trapping sediments and filtering pollutants – but that's not all.
Download the Wetlands PDF for more information.