Freshwater Wetlands - Hydro-Environmental Analysis: Freshwater Environments - page 511

TABLE 19.1
Examples of Wetland Deinitions

Source Deinition

USEPA Ofice of Wetlands,
Oceans, and Watersheds

“Wetlands are areas where water covers the soil, or is present either at or near the surface
of the soil all year or for varying periods of time during the year, including during the
growing season.”

U.S. Fish and Wildlife Service
nonregulatory deinition
(Cowardin et al. 1979)

“Wetlands are lands transitional between terrestrial and an aquatic system where the
water table is usually at or near the surface or the land is covered by shallow water.”
For the purposes of this classiication, wetlands must have one or more of the following
three attributes: (1) at least periodically, the land supports predominantly hydrophytes;
(2) the substrate is predominantly undrained hydric soil; and (3) the substrate is nonsoil
and is saturated with water or covered by shallow water at some time during the
growing season of each year.

U.S. Army Corps of Engineers
(33 CFR 328.3) U.S.
Environmental Protection
Agency (40 CFR 230.3)

“Wetlands are those areas that are inundated or saturated by surface or groundwater at a
frequency and duration suficient to support, and that under normal circumstances do
support, a prevalence of vegetation typically adapted for life in saturated soil
conditions. Wetlands generally include swamps, marshes, bogs, and similar areas.”

U.S. Soil Conservation
Service (National Food
Security Act manual [SCS
1988]) (The act is commonly
known as the Swampbuster)

“Wetlands are deined as areas that have a predominance of hydric soils and that are
inundated or saturated by surface or ground water at a frequency and duration suficient
to support, and under normal circumstances do support, a prevalence of hydrophytic
vegetation typically adapted for life in saturated soil conditions, except lands in Alaska
identiied as having high potential for agricultural development and a predominance of
permafrost soils.”

signiicant inlows or outlows of water so that most of their moisture is accumulated from rainfall.
Similarly, fens are a type of peatland, but they are slightly more alkaline with a higher species
d iversit y.
One plant commonly associated with bogs is the carnivorous pitcher plant (see Figure 19.2).
While bogs are low in nutrients, they typically have ample light and moisture. The pitcher plant
overcomes the low nutrients and low productivity of bogs by capturing insects in their leaves and
digesting them in deep, slippery pools illed with digestive enzymes, with the aid of symbiotic
bacteria. A variety of other carnivorous plants commonly occur in bogs and fens and as many
as 13 species of carnivorous plants have been found in a single bog (Folkerts 1982).
One of the problems with bogs and fens is that they are dificult or impossible to replace. As
will be discussed later, mitigation is commonly used to compensate for wetlands that have been
damaged or destroyed. However, in “Compensatory Mitigation for Losses of Aquatic Resources
(33 C.F.R. Part 332),” bogs, fens, springs, streams, and Atlantic white cedar swamps are identiied
as “dificult to replace resources” (Gardner 2011), strongly encouraging the avoidance of activities
impacting these wetland types.

19.2.2 n ontIdaL (I nLand or f reSHwater ) M arSHeS
Freshwater marshes are wetlands that are frequently or continually inundated with water, and are
characterized by emergent soft-stemmed vegetation, as opposed to trees and shrubs that charac-
terize swamps. Marshes constitute one of the most commonly occurring natural wetlands. Man-
made marshes, constructed wetlands, are also becoming increasingly used as a best management
practice (BMP) to control looding or for nutrient removal (e.g., ASCE 1992). There is a wide
variety of freshwater marshes, including playa lakes, prairie potholes, and wet meadows or prairies
(Figure 19.3).