Wetlands Serve Important, Varied Functions

Vegetation, hydrology and hydric soils are indicators of wetland tracts
Wednesday, November 16, 2005

Wetlands are extremely important features, particularly in coastal areas. Among their many functions are stormwater storage, erosion control, water purification, sediment trapping, nutrient removal, groundwater discharge and recharge, and providing animal and plant habitat.

Wetlands are also intrinsically valued, providing opportunity for production of food for people and animals, fuel, timber, recreation, aesthetics and education.

But what does a wetland look like? Coastal wetlands include salt marshes, shrub wetlands, brackish marshes, bottomland hardwood swamps and depressional wetlands. But you may not be able to tell any of these, depending on the time of year. Wetlands are technically defined as those areas saturated by surface or ground water often and long enough to support vegetation typical of saturated soil conditions.
There are three categories of wetland indicators. Indicators must be present in all three categories for an area to be considered a wetland. These indicators are vegetation (presence of hydrophytic, or "water loving," vegetation), hydrology (the duration that water impacts a wetland) and hydric soils (soils that are saturated with water for a long period of time).

Indications of hydrophytic vegetation include buttressing of tree trunks and tree "knees." Indicators of hydrology include standing water, dark-colored water marks on tree trunks and leaves on the ground that are gray or stained. Indications of hydric soils include soils that may be blue-gray, greenish or gray in color below the surface, soils that will "ribbon" when squeezed in your hand, soil that may be saturated with water and indications of oxidation (rust-colored areas) around plant root zones.

The U.S. Army Corps of Engineers holds jurisdiction over wetlands in the United States. To be certain if you have a wetland on your property, contact the corps or a qualified scientific laboratory for a wetlands determination.

(Jody A. Thompson is an environmental extension assistant at Auburn University Marine Extension and Research Center. Sea Grant writers may be contacted at 438-5690. )