National Academies Press: OpenBook

Wetlands: Characteristics and Boundaries (1995)

Chapter: APPENDIXES

« Previous: REFERENCES
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

APPENDIX
A

Soil Taxonomy

SOIL NOMENCLATURE 101

The U.S. system of soil taxonomy is hierarchical (Soil Survey Staff, 1975). The most general level in the hierarchy is soil "order": Alfisols, Andisols, Aridisols, Entisols, Histosols, Inceptisols, Mollisols, Oxisols, Spodosols, Ultisols, and Vertisols. Wetland soils occur in all 11 orders. Histosols are organic soils, formed almost exclusively in wetlands, whereas the other orders are mineral soils.

The second level in the taxonomic hierarchy is "suborder." Many wetland soils are in Aquic suborders, and they have an aquic moisture regime. Aquic suborders occur in all soil orders except Histosols, Oxisols, and Vertisols (wetland soils in these orders have other suborders). The names of Aquic suborders have two syllables, the first of which is "Aqu" and the second of which defines the soil order. For example, the suborder of Entisols that have an aquic moisture regime is "Aquents.''

The third level in the taxonomic hierarchy is the "great group." The names of great groups are one word with three or more syllables, of which the last two denote the suborder. For example, an Aquent with very young sediments from frequent flooding is a "Fluvaquent."

The fourth level in the taxonomic hierarchy is "subgroup," used to modify the great group. For example, an "Aquic Xerofluvent" is an Entisol with very young sediments in a Mediterranean climate (Xerofluvent) that is saturated with water within 4.92 ft (1.5 m) of the surface during any period of most years. Aquic subgroups occur in all soil orders except Histosols.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

The definition of "hydric soils" (Soil Conservation Service, 1991) distinguishes specific suborders, great groups, and subgroups so it is important to understand those terms.

SOIL MOISTURE REGIME

In soil taxonomy, "soil moisture regime" refers to the presence or absence either of ground water or of water held at a tension of less than 1500 kilopascals (kPa) (Soil Survey Staff, 1992, p. 34). Wetland soils generally have "aquic" or "peraquic" moisture regimes:

Aquic moisture regime. The aquic moisture regime signifies a reducing regime in a soil that is virtually free of dissolved oxygen because it is saturated by ground water or by water of the capillary fringe. Some soils at times are saturated with water while dissolved oxygen is present, either because the water is moving or because the environment is unfavorable for microorganisms (e.g., if the temperature is less than 34°F [I°C]); such a regime is not considered aquic.

It is not known how long a soil must be saturated to have an aquic regime, but the duration must be at least a few days, because it is implicit in the concept that dissolved oxygen is virtually absent. Because dissolved oxygen is removed from ground water by respiration of micro-organisms, roots and soil fauna, it is also implicit in the concept that the soil temperature is above biologic zero (5°C) at some time while the soil or the horizon is saturated.

Very commonly, the level of ground water fluctuates with the seasons; it is highest in the rainy season, or in fall, winter, or spring if cold weather virtually stops evapotranspiration. There are soils, however, in which the ground water is always at or very close to the surface. A tidal marsh and a closed, landlocked depression fed by perennial streams are examples. The moisture regime in these soils is called "peraquic."

Although the terms aquic and peraquic moisture regime are not used either as criteria or as formative elements for taxa, they are used as an aid in understanding genesis.

These definitions are purely scientific, unrelated to any wetland regulation. Therefore, an "aquic soil" (Soil Survey Staff, 1994) might or might not be a "hydric soil" (SCS, 1991).

AQUIC CONDITIONS

The term aquic conditions was introduced in 1992 as a result of recommendations submitted to the Soil Conservation Service by the International Committee on Aquic Moisture Regime (ICOMAQ), which was established in 1982 (Soil Survey Staff, 1994). Soils with aquic conditions are those that currently experience continuous or periodic saturation and reduction. The presence of these

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

conditions is indicated by redoximorphic features and can be verified, except in artificially drained soils, by measuring saturation and reduction. The following description of aquic conditions (saturation, reduction, and redoximorphic conditions) is from "Keys to Soil Taxonomy" (Soil Survey Staff, 1994, p. 25-29).

Elements of Aquic Conditions

  1. Saturation is characterized by zero or positive pressure in the soil-water and can generally be determined by observing free water in an unlined auger hole. However, problems may arise in clayey soils with peds, where an unlined auger hole may fill with water flowing along faces of peds while the soil matrix is and remains unsaturated (bypass flow). Such free water may incorrectly suggest the presence of a water table, while the actual water table occurs at greater depth. Use of well-sealed piezometers or tensiometers is therefore recommended for measuring saturation.

The duration of saturation required for creating aquic conditions is variable, depending on the soil environment, and is not specified. Three types of saturation are defined:

  1. Endosaturation - The soil is saturated with water in all layers from the upper boundary of saturation to a depth of 200 cm or more from the mineral soil surface.

  2. Episaturation - The soil is saturated with water in one or more layers within 200 cm of the mineral soil surface and also has one or more unsaturated layers, with an upper boundary above 200 cm (78 in.) depth, below the saturated layer. The zone of saturation, i.e., the water table, is perched on top of a relatively impermeable layer.

  3. Anthric saturation - This variant of episaturation is associated with controlled flooding (for such crops as wetland rice and cranberries), which causes reduction processes in the saturated, puddled surface soil and oxidation of reduced and mobilized iron and manganese in the unsaturated subsoil.

  1. The degree of reduction in a soil can be characterized by the direct measurement of redox potentials. Direct measurements should take into account chemical equilibria as expressed by stability diagrams in standard soil textbooks. Reduction and oxidation processes are also a function of soil pH. Accurate measurements of the degree of reduction existing in a soil are difficult to obtain. In the context of Soil Taxonomy, however, only a degree of reduction that results in reduced Fe (iron) is considered, because it produces the visible redoximorphic features that are identified in the keys. A simple field test is available to determine if reduced iron ions are present when the soil is saturated. A freshly broken surface of a field-wet soil sample is treated with α α'-dipyridyl in neutral, l-normal ammonium-acetate solution. The appearance of a strong red color on the

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

freshly broken surface indicates the presence of reduced iron ions. Use of α, α'-dipyridyl in a 10-percent acetic-acid solution is not recommended because the acid is likely to change soil conditions, for example by dissolving CaCO3.

The duration of reduction required for creating aquic conditions is not specified.

  1. Redoximorphic features associated with wetness result from the reduction and oxidation of iron and manganese compounds in the soil after saturation with water and desaturation, respectively. The reduced iron and manganese ions are mobile and may be transported by water as it moved through the soil. Certain redox patterns occur as a function of the patterns in which the ion-carrying water moves through the soil, and of the location of aerated zones in the soil. Redox patterns are also affected by the fact that manganese is reduced more rapidly than iron, while iron oxidizes more rapidly upon aeration. Characteristic color patterns are created by these processes. The reduced iron and manganese ions may be removed from a soil if vertical or lateral fluxes of water occur, in which case there is no iron or manganese precipitation in that soil. Wherever the iron and manganese is oxidized and precipitated, it forms either soft masses or hard concretions or nodules. Movement of iron and manganese as a result of redox processes in a soil may result in redoximorphic features that are defined as follows:

  1. Redox concentrations - These are zones of apparent accumulation of Fe-Mn (iron-manganese) oxides.

  2. Redox depletions - These are zones of low chroma (2 or less) where either Fe-Mn oxides alone or both Fe-Mn oxides and clay have been stripped out.

  3. Reduced matrix - This is a soil matrix which has a low chroma in situ, but undergoes a change in hue or chroma within 30 minutes after the soil material has been exposed to air.

  4. In soils that have no visible redoximorphic features, a positive reaction to an α, α'-dlpyridyl solution satisfies the requirement for redoximorphic features.

OTHER TERMS RELATED TO SOIL WETNESS

Natural Drainage Classes

Soils are assigned to natural drainage classes according to the frequency and duration of wet periods under conditions similar to those that existed when the soil developed (Soil Survey Staff, 1993). In the field, soil surveyors infer soil drainage by differences in soil color and in patterns of soil color. Soil slope, texture, structure, and other characteristics also are useful for evaluating soil drainage conditions. There are seven soil drainage classes, ranging from "very poorly drained" to "excessively drained." The three wettest categories, as defined in the Soil Survey Manual (Soil Survey Staff, 1993, pp. 99-100) are described below:

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
  • Very poorly drained. Water is removed from the soil so slowly that free water remains at or very near the ground surface during much of the growing season. The occurrence of internal free water is very shallow and persistent or permanent.

  • Poorly drained. Water is removed so slowly that the soil is wet at shallow depths periodically during the growing season or remains wet for long periods. The occurrence of internal free water is shallow or very shallow and common or persistent.

  • Somewhat poorly drained. Water is removed slowly so that the soil is wet at a shallow depth for significant periods during the growing season. The occurrence of internal free water commonly is shallow to moderately deep and transitory to permanent.

Soil Inundation

Inundation is the condition of soil when an area is covered by liquid free water (Soil Survey Staff, 1993). Flooding is temporary inundation by flowing water. If the water is standing, as in a closed depression, the term "ponding" is used.

Older soil surveys used four classes of flooding frequency (Soil Survey Staff, 1951):

  1. Floods frequent and irregular, so that any use of the soil for crops is too uncertain to be practicable.

  2. Floods frequent but occurring regularly during certain months of the year, so that the soil may be used for crops at other times.

  3. Floods may be expected, either during certain months or during any period of unusual meterological conditions, often enough to destroy crops or prevent use in a specified percentage of the years.

  4. Floods rare, but probable during a very small percentage of the years.

REFERENCES

Soil Conservation Service. 1991. Hydric Soils of the United States, Third Edition. Soil Conservation Service, Miscellaneous Publication Number 1491. Washington, DC.

Soil Survey Staff. 1951. Soil Survey Manual. USDA Handbook 18. U.S. Government Printing Office, Washington, DC.

Soil Survey Staff. 1975. Soil Taxonomy. USDA Soil Conservation Service Agric. Handb. No. 436. U.S. Government Printing Office, Washington, DC.

Soil Survey Staff. 1992. Keys to Soil Taxonomy, fifth edition. SMSS Monogr. No. 19. Pocahontas Press, Blacksburg, VA.

Soil Survey Staff. 1993. Soil Survey Manual. USDA Handbook 18. U.S. Government Printing Office, Washington, DC.

Soil Survey Staff. 1994. Keys to Soil Taxonomy, 6th ed. USDA-SCS. U.S. Government Printing Office, Washington, DC.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

APPENDIX
B

Case Histories

CASE HISTORY 1

Kirkham Wetlands, Talbot County, Maryland Seasonal Hydrologic Change and Microtopography in Forested Wetlands

The Kirkham wetlands are typical of several hundred thousand acres of forested wetland in Maryland and adjoining states. These wetlands are located on flat topography and are supported hydrologically by the presence of ground water near the soil surface; the ground water is maintained by precipitation.

Figure B1.1 shows the location of the Kirkham wetlands, and the area can be used to illustrate many of the challenges for characterizing and delineating forested wetlands in Maryland and adjoining states. The U.S. Army Corps of Engineers (USACE) has obtained data on soils, vegetation, and surface hydrology, which would be typical support for delineations in this region. It also has gathered information on ground water, which typically is not available for delineations because it is expensive and time-consuming to collect and would delay the delineation process by at least a year if it were required.

The soils of the Kirkham site belong to the Elkton series (Elkton silt loam) and are classified as Typic Ochraquults. The soil profile consists of 4 to 10 in. (10.16-25.4 cm) of silt loam; the subsoil consists of about 30 in. (76.2 cm)of silty clay and silty clay loam. Below the subsoil is sand with much higher permeability. The soils have a dominant chroma of 2 or less below the A horizon. The soils show mottling caused by oxidized iron at depths where seasonal water saturation is characteristic.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B1.1 General location map for the Kirkham wetlands.

The dominant tree species throughout the site are loblolly pine (Pinus taeda) and red maple (Acer rubrum), as well as the shrub, and coast pepperbush (Clethra alnifolia) (Table B1.1). Red maple can appear in the understory, which is not rich in other species or in vines or herbaceous plants. Gaps could support other species, however. One large gap created by gypsy moth damage to trees showed an extensive growth of wool grass (Scirpus cyperinus), a facultative-wet (FACW+) species.

The indicator status of the plant community can change when the overstory is removed. For example, removal of trees could reduce depletion of ground

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

TABLE B1.1 Plant Community Composition for the Kirkham Site

 

 

 

Location (station number)

Species

Common

name

Statusa

1

2

3

4

5

6

7

Quercus alba

White oak

FACU-

-

-

-

-

-

-

-

Pinus taeda

Loblolly Pine

FAC-

X

X

X

X

X

X

-

Acer rubrum

Red maple

FAC

X

X

X

X

X

-

X

Clethra alnifolia

Cost pepperbush

FAC+

X

X

X

X

X

X

X

Liquidambar styraciflua

Sweetgum

FAC

-

-

-

-

-

-

X

Parthenocissus quinquefolia

Virginia creeper

FACU

-

-

-

-

-

-

-

Toxicodendron radicans

Poison ivy

FAC

-

-

-

-

-

-

-

Fagus grandifolia

American beech

FACU

X

-

-

-

-

-

-

Vaccinium corymbosum

Highbush blueberry

FACW-

-

-

-

X

-

-

-

Carex intumescens

Bladder sedge

FACW+

-

-

-

X

-

-

-

Graminae

Grasses

--

-

-

-

-

X

-

X

Quercus falcata var. pagodifolia

Cherrybark oak FACW

-

-

-

-

-

-

X

 

a FAC, facultative species; FACU, facultative-upland species; FACW, facultative-wet species.

water by evapotranspiration, thus converting sites from marginal or indeterminate to wetland. Soil compaction could have similar effects.

Some portions of the Kirkham site show surface hydrologic indicators of wetland status, including water marks on trees and blackened leaves. A site visit between January and May might show water standing at the surface over these portions of the site, but a visit at other times of the year would not. Because of microtopographic variation, which falls within a range of 29.25 in. (75 cm), large portions of the site show no evidence of surface hydrology. Figure B1.2, which gives surface contours, shows that the surface indicators of hydrology are distributed irregularly.

Water table data from wells show the hydrologic boundaries for wetlands at the Kirkham site. Figure B1.3 shows the records from a single well over a period of 3 years. Patterns from other wells at the site are similar, although the proximity of the water table to the surface depends on elevation at a particular location. As shown by Figure B1.3, there is a strong seasonal variation in the water table at the Kirkham site. The highest water tables are found in late winter or spring. It is clear from the well records that hydrologic classification based on well data

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B1.2 Microtopography and location of monitoring wells for a portion of the Kirkham wetlands (derived from a map prepared by USACE).

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B1.3 Depth to ground water as a function of season for  3 years at the Kirkham wetlands site.

would be erroneous if the well data did not include that portion of the year when the water table is highest. Furthermore, irregularities of timing in the rise of the water table from one year to the next suggest that a single datum taken at almost any time of the year could be in error.

USACE delineated the Kirkham site according to the guidelines in the 1987 manual (Figure B1.2). Hydric soils extended over the entire site and beyond the margin of wetland vegetation.

In this sense, the soils were important in contributing to the classification of the site as a wetland, but they were not useful in setting the boundary for the wetland according to the 1987 criteria. The boundary was drawn at the vegetative margin corresponding to 50% composition of species classified as FAC (facultative species) or wetter. This margin was then verified and refined by the use of surface indicators of hydrology, such as blackened leaves, Subsequent study of the data on ground water hydrology confirmed that the entire site would meet the hydrologic requirements for wetland classification. However, the study

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

also showed that exclusive reliance on ground water data would have required 1 year or more of data collection because of the extreme seasonal variation in ground water levels.

Had the site been delineated by the 1989 manual rather than by the 1987 manual, delineation would have been simpler because it could have been based solely on the margins of hydric soils. This would have resulted in a slightly larger area for the delineation, given that the hydric soils extend further upslope than do the hydrophytic vegetation or the surface indicators of hydrology. Delineation according to 1991 proposed revisions probably would have resulted in exclusion of the site from classification as a wetland because of stricter requirements for classification of vegetation.

The future of the Kirkham wetlands could be beyond the influence of any delineation method. These wetlands are classified hydrologically as ''isolated'' because they are maintained by ground water rather than by a surface hydrologic connection to navigable waters. For this reason; the Kirkham wetlands are covered by Nationwide Permit 26, which allows conversion of wetland blocks of up to 1 acre (0.4 ha) without notification of USACE. It also allows conversion of 1-10 acre (0.4-4.0 ha) blocks with a predischarge notification but minimal review by USACE. Therefore, it is possible that all or part of the Kirkham wetlands could be incrementally altered under Nationwide Permit 26, regardless of the delineation boundaries.

CASE HISTORY 2

Yazoo National Wildlife Refuge Lower Mississippi Valley Relict Soils and Altered Hydrology

Wetlands occupied by bottomland hardwood forest account for many millions of acres in the southeastern United States (Clark and Benforado, 1981). The soils associated with these wetlands are frequently well suited for agriculture if they can be drained. Consequently, the total acreage of bottomland hardwood has declined substantially since the turn of the century (Gosselink and Maltby, 1990). This is well illustrated by Gosselink's study of the Tensas River bottomland of Louisiana (Gosselink et al., 1990) (Figure B2.1). Until the recent tightening of restrictions on drainage of wetlands for agricultural purposes (the "swampbuster" provisions of the Food Security Act of 1985), the rate of drainage and clearing often reflected fluctuations in the price of crops, principally soy-beans, that could be grown on drained lands. In addition, use of lands subject to seasonal inundation has steadily become more practical with the introduction of new genetic strains that show rapid rates of maturation.

The lands of the Vicksburg District of the USACE illustrate several characteristics of extensive wetland supporting bottomland hardwood forest. The

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B2.1 Disappearance of bottomland hardwood forest from the floodplain of the Tensas River, Louisiana. Different symbols indicate estimates from different sources. Source: Gosselink et al., 1990. Landscape conservation in a forest wetland watershed. BioScience 40:588-600. ©1990 American Institute of Biological Sciences.

Vicksburg District encompasses 45 million acres (18 million ha), including 18 million acres (7.2 million ha) of floodplain ("delta"). About 70% of the floodplain is cleared. When identification and delineation of wetlands became an issue in the 1970s, the district identified 1.5 million acres (0.6 million ha) of wetland by the use of regional criteria for wetland delineation. In 1987, the first standard delineation manual was made available, but the district continued to use regionally derived procedures that had been in use since the 1970s. When the 1989 manual was introduced, a quick assessment showed that literal interpretation of the 1989 criteria might increase the amount of jurisdictional wetland from 1.5 million acres (0.6 million ha) to 12 million acres (4.8 million). It became clear that this amount would be reduced substantially by exclusion of "prior converted" agricultural lands, but even so would result in a substantial increase in the area of jurisdictional wetland. Under current practice, the USACE Vicksburg District uses the 1987 manual for identification and delineation of wetlands. This approach defines approximately 4.5 million acres (1.8 million ha) of wetland in the district.

Studies of the Steele Bayou wetlands of the Yazoo National Wildlife Refuge have provided information on some of the issues that arise in the delineation of

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

wetlands supporting bottomland hardwood forest. Steele Bayou is located just east of the Mississippi River north of Vicksburg (Figure B2.2). As is characteristic of the bottomland hardwood wetlands of this region, the Steele Bayou wetlands show a hydrologic regime that reflects seasonal flooding along the lower Mississippi River. Because the Steele Bayou is near the junction of the Yazoo River with the Mississippi, drainage is impeded as the Mississippi River reaches its seasonal peak discharge. Annual water level fluctuations in Steele Bayou can exceed 9 ft (3 m).

Bottomland hardwood forests and their adjacent aquatic and upland habitats of the southeastern United States are conventionally divided into six zones as defined by hydrologic characteristics (Larsen et al., 1981) (Figure B2.3). The zones can be loosely designated as aquatic (I), swamp (II), lower hardwood wetland (III), medium hardwood wetland (IV), upper hardwood wetland (V), and upland (VI). Delineation by the 1987 manual typically places the wetland boundary between zones IV and V.

Figure B2.4 shows the zonation of the Steele Bayou wetlands along a transect that has been used extensively for analysis of soils and hydrologic characteristics. The zones reflect elevation contours that extend from the water surface of the bayou up to a ridge that was formed as a natural levee when the Mississippi and its tributaries in this region probably followed somewhat different courses than they do today.

The soils of the Steele Bayou wetland range from Dundee series (Aeric Ochraquolt) on the ridge to Sharkey series (Vertic Haplaquept) at points nearer to the bayou. The Dundee soils are of medium to fine texture, generally poorly drained, and dark brown to gray-brown, often with mottling. Sharkey soils are poorly drained, with high clay content, and are typically dark gray to dark gray-brown. In a laboratory setting, all of the soils between the bayou and the ridge might be classified as hydric on the basis of chroma and under indicators. From the field setting, it is clear that the Dundee soil of the ridge is not inundated under the current hydrologic regime. The Steele Bayou site thus indicates the problem of relict soils: Hydric soils that formed under wetland conditions continue to show hydric characteristics after the hydrologic conditions change. Under these circumstances, the establishment of wetland boundaries by the use of soil can be unreliable unless soil phases that clearly reflect current conditions can be identified.

Detailed studies of oxygen content, redox potential, and water depth below the soil surface illustrate some of the critical differences for development of wetlands at the Steele Bayou site (Figure B2.5) (Faulkner et al., 1991). At location 1, along the ridge, the soil contains substantial oxygen and shows high redox potentials, consistent with the growth of plants that have poor tolerance for anaerobic conditions or for chemical conditions associated with low redox potentials. The water table remains 3 ft (0.9 m) or more below the surface at this site, regardless of season. In contrast, location 3 shows strong seasonal depletion of

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B2.2 General location of the Steele Bayou site.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B2.3 Illustration of zonation for bottomland hardwood forests of the  southeastern United States (from Theriot [1993] after Clark and Benforado [1981]).

FIGURE B2.4 Map of the Steele Bayou site showing zonation.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B2.5 Oxygen, redox potential, and water table level in zones VI and IV  of the Steele Bayou wetlands. Source: from Faulkner et al., 1991.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B2.6 Change in abundance of wetland vegetation across zones in the Steele Bayou wetlands (data from USACE, Vicksburg District). A prevalence index below 3.0 indicates wetland vegetation.

oxygen and suppression of redox potentials. These seasonal events correspond to a rise in the water table to points reaching or exceeding the soil surface.

Woody vegetation in the Steele Bayou wetlands ranges from sassafras (Sassafras albidum), sweetgum (Liquidambar styraciflua), and oak (Quercus nigra) on the ridge to willow (Salix nigra) and cypress (Taxodium distichum) at the lowest elevations. The prevalence of other moisture-tolerant species increases steadily from the lowest to the highest elevations.

Theriot (1993) analyzed the association between vascular plant species and hydrologic regimes at 17 sites, including the Steele Bayou site, in the southeastern United States. Multivariate statistical analysis showed a strong association between community composition and hydrologic regime. Trees provided the best discrimination of sites, and herbaceous vegetation was least effective. The accuracy of classification based on tree species composition alone was 82%. This principle is illustrated for the Steele Bayou site by the graded change in community composition across hydrologic zones (Figure B2.6), which reflects the hydrologic gradient.

Hydrologic conditions at the Steele Bayou site have been affected by a drainage project that was completed in 1988. This USACE-sponsored project involved extensive wetlands mitigation in compliance with National Environmental Protection Act (NEPA) requirements. The project resulted in reduction of the level of the mean annual flood at Steele Bayou by about 23 in. (60 cm), Hydrologic change resulting from the project could be the basis for a change in the location of the wetland boundary and in a shift in the zonation of the Steele

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

Bayou area. Soils throughout the site will remain hydric, as they are now, even when hydrologic conditions change. Vegetation will probably change, but only gradually. Mature trees reflect hydrologic conditions over the past several decades and will not be affected quickly by a change in hydrologic conditions. However, recruitment of new individuals through the establishment of seedlings will be affected. In fact the first signs of this are already evident in the appearance of seedlings and young saplings of upland taxa at elevations lower than they have been found in the past. The Steele Bayou site thus provides a good example of the low sensitivity of woody vegetation to hydrologic change over the short term, even though community composition will change to reflect hydrology over the long term.

Until the hydrology changed, delineation of the wetland boundary at the Steele Bayou site was relatively straightforward on the basis of plant community composition and surface indicators of hydrology. At present, delineation would be more difficult, given that surface indicators of hydrology are beginning to disappear from the sites that still support a wetland plant community.

References

Clark, J.R. and J. Benforado (eds.). 1981. Wetlands of Bottomland Hardwood Forests. Elsevier, NY.


Faulkner, S.P., W.H. Patrick, Jr., W.B. Parker, R.P. Gambrell, and B.J. Good. 1991. Characterization of soil processes in bottomland hardwood wetland-nonwetland transition zones in the lower Mississippi River Valley. Contract Rep. WRP-91-1. Vicksburg, MS: U.S. Army Corps of Engineers, Waterways Experiment Station.


Gosselink, J.G., G.P. Shaffer, L.C. Lee, D.M. Burdick, D.L. Childers, N.C. Leibowitz, S.C. Hamilton, R. Boumans, D. Cushman, and S. Fields. 1990. Landscape conservation in a forest wetland watershed. BioScience 40:588-600.

Gosselink, J.G. and E. Maltby. 1990. Wetland losses and gains. Pp. 296-322 in M. Williams, ed. Wetlands: A Threatened Landscape. Blackwell, Oxford.


Larson, J.S., M.S. Beidinger, C.F. Bryan, S. Brown, R.T. Huffman, E.L. Miller, D.G. Rhodes, and B.A. Touche. 1981. Transition from wetlands to uplands in southeastern bottomland hardwood forests.


Theriot, R.F. 1993. Flood tolerance of plant species in bottomland forests of the southeastern United States. Vicksburg, MS: US Army Corps of Engineers Waterways Experiment Station Technical Report WRP-DE-6.

CASE HISTORY 3

Verde River Wetlands Yavapai County, Arizona Growing-Season Definitions and Western Riparian Lands

The Verde River, which joins the Salt River east of Phoenix, Arizona, drains an area of approximately 6,200 mi2 (16,120 km2), including 13 tributary watersheds (Figure B3.1) (Sullivan and Richardson, 1993). Over at least half of its

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B3.1 Location of the Verde River reach, containing Dead Horse Ranch State Park (Reach 2B).

length, the Verde River and the lower reaches of its tributaries support a well-developed riparian zone situated on lateral floodplain. In addition, the river channel and adjacent floodplain contain depressions that are moist at varying intervals, depending on their elevation above the river.

The riparian zone and river Channel depressions of the Dead Horse Ranch State Park provide examples of several problems in delineation and identification of wetlands in the western United States. The Verde River channel in the vicinity of Dead Horse Ranch State Park contains depressions that were created by erosion at high flow. These depressions are typically a few feet to tens of feet in

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

their longest dimension. They are most likely to be wet during the winter months, when river discharge can briefly occupy the entire channel. During the growing season, which extends from March through October in the lower reaches of the Verde River, these sites are likely to be dry. They lack extensive woody vegetation, although some support populations of the Goodding willow (Salix gooddingii). Herbaceous taxa include representatives of the obligate or facultative-wet categories such as bulrushes (Scirpus americanus), sedges (Cyperis odoratus), and rushes (Juncus Terri). The presence of these plants, which require saturation or inundation for establishment and growth, suggests that the growing season is erroneously defined, at least with respect to wetland plants. The depressions also can lack soils, given that they are established through the movement of coarse sediment, and thus might not be easily defined by any criteria that require the presence of hydric soils. These wetlands are protected as waters of the Unites States because of their location within the normal high-water zone of the channel, but they are difficult to classify as wetlands because they lack soils and they fail to show the requisite hydrology during the formally defined growing season.

Above the river channel and separated from it by a steeply cut bank is a floodplain terrace that was established by floods of decadal or longer recurrence. This terrace contains depressions of varying size and depth that are comparable in dimensions to those found in the channel itself. The depressions show weak or negligible soil development and are inundated so seldom that they typically cannot meet the criteria for inundation or saturation, particularly during the growing season. Some of the depressions are deep enough to support wetland plants because of their proximity to ground water; others are not.

The entire riparian zone, which extends above the channel along the floodplain, presents severe problems in the identification and delineation of wetlands. This zone is not saturated annually. The underlying aquifer is relatively close to the surface (a few feet) but typically does not approach the surface closely enough to meet standard criteria for saturation at or ''near'' the surface. In fact, the entire system is established and maintained by floods that have recurrence intervals of many years, rather than annually, as would be the case in large portions of the southeastern bottomland hardwood forest (Zone II). Flooding redistributes the substrate, which is predominantly sand rather than hydric soil, and provides the essential conditions for establishment of key woody plants, such as cottonwood and willow (Stromberg et al., 1991). Once established, woody species can persist throughout their entire lifespan without additional flooding, because they are able to use the abundant water that is present in the phreatic zone. These woody species require inundation for establishment but, once established, can and typically do persist for very long periods of time without further inundation.

The riparian zone of the Verde River is dominated by Fremont cottonwood (Populus fremontii), Goodding willow (Salix gooddingii), salt cedar (Tamarix chinensis), alder (Alnus oblongifolia), and box elder (Acer negundo). Shrubs are

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

not abundant, and herbaceous vegetation consists primarily of grasses, most of which lack wetland affinity because they grow in an environment that is seldom wet at the surface. The riparian zone lies above the normal high water mark and is therefore unprotected unless it can be classified as wetland.

The classification of western riparian zones such as those of the Verde River is problematic. Application of the 1987 USACE manual to these areas would probably show that they are not wetlands. The riparian zones of the west serve virtually all of the functions that are identified with bogs, swamps, and marshes of the wetter parts of the United States (Sullivan and Richardson, 1993). These zones are particularly important in stabilizing flood flows, which are especially destructive in arid zones such as the Verde River watershed. Vegetation stabilizes sediment, even under flood conditions. The riparian zones store and transport extensive alluvial water below the surface. Unique species associations of vegetation, vertebrates, and invertebrates are characteristic of the western riparian zones, which often are centers of biodiversity when compared with surrounding uplands. The recreational and aesthetic importance of these areas is also especially high. Surveys at the Dead Horse Ranch State Park site along the Verde River show 162 species of birds, including several listed as endangered and threatened species by the federal and state government; the avifauna includes shore birds, waterfowl, and tropical migrants. The channel and floodplain depressions of the Verde River can be classified as wetland only by liberal use of the guidelines now in use for identification of wetlands. It is also clear that the entire riparian zone performs the same functions that are performed by more easily identified wetlands in other parts of the country and that they are occupied by a distinctive flora that can be established only by inundation. The paradox is whether to include these areas by broadening the identification of wetlands, which might result in inadvertent inclusion of some eastern upland regions, to treat western riparian lands as wetlands by exception, or to regulate western riparian lands for their own sake, thus avoiding the problem of dealing with them through the wetlands classification system.

References

Stromberg, J.C., D.T. Patten, and B.D. Richter. 1991. Flood flows and dynamics of sonoran riparian forests. SEL and Associates.

Sullivan, M.E., and M.E. Richardson. 1993. Functions and values of the Verde River riparian ecosystem and an assessment of adverse impacts to these resources. USEPA Region IX, San Francisco, CA.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

CASE HISTORY 4

Hydric Pine Flatwoods of Southwest Florida Indistinct Margins and the Role of Fire

Flatwood wetlands of Florida consist of seasonally inundated lands that have sandy soils or sand substrates; a canopy that is often incomplete in coverage and consisting of slash pine; and a mixed understory of grasses, shrubs, and forbs that are tolerant of fire and inundation (Abrahamson and Harnett, 1990). In southwest Florida, this general wetland type takes the form of hydric pine flatwood, which occupies approximately 200,000 acres (80,000 ha). This wetland type has been reduced in extent by about 50% since 1970 (Birnhak and Crowder, 1974). Economic forces that have produced drainage of pine flatwood include commercial and residential development, citrus farming, and silviculture. Hydric pine flatwood is a distinctive regional wetland type that presents problems primarily associated with weak boundary definition and interaction between fire, water, and grazing.

The hydric pine flatwoods of southwestern Florida lie on a calcareous substrate derived from marine transgression and showing very little relief or slope (0.0016%). Because the terrain is flat, headwater streams are not well defined, and overland flow is the predominant means of water movement during the wet season. The hydric pine flatwoods are bordered by mesic and xeric pine flatwoods that are distinguished from them by vegetation, soils, and hydrologic characteristics. However, because of the gentle gradient, the margin between hydric zones, which are wetlands, and mesic or xeric zones, which are not, is indistinct. The gentle gradient in topography is reflected not only by gentle gradients in wetland indicators, but by a magnified importance of minor features of relief such as mounds that are only a few inches high and yet appear as mesic islands mixed with surrounding hydric terrain (Figure B4.1).

Southwestern Florida receives the bulk of its precipitation between May and September and shows a pronounced dry season between November and April. Toward the end of the dry season, the water table of hydric pine flatwoods can be as much as 3 ft (0.9 m) below the surface. In some cases, the water table is held by a hardpan that separates the surface aquifer from deeper aquifers. In spring, precipitation saturates the soil and raises the water table to the surface. Drainage is so weakly developed, and the amount of precipitation is so great, that the hydric pine flatwoods become fully inundated and remain so for at least 2 months. Water depths at the height of inundation reach as much as 3 ft, but they are characteristically in the vicinity of 1 ft. Adjacent mesic flatwoods also can be inundated, but to a shallower depth and over a shorter duration.

As precipitation declines, slow drainage of surface water occurs and the water table recedes below the soil surface and subsequently becomes very dry. Although the flatwoods show minimal relief, some mosaic elements, including

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B4.1 The margin of a hydric pine flatwood wetland in southwestern Florida. The appropriate wetland demarcation line would be between the hydric and mesic zones, but the transition is gradual and is marked by irregular inclusions of one zone within another.

sloughs and depressions, retain water throughout the dry season, and in this way introduce habitat diversity and refugia for organisms that require water continually.

The hydric pine flatwoods have distinctive vegetation. The canopy is dominated typically by slash pine (Pinus elliottii var. densa). The understory is diverse and varied spatially in relation to such factors as frequency of fire, duration of drying, and depth of inundation. Some of the larger plants in the understory include cabbage palm (Sabal palmetto), wax myrtle (Myrica cerifera), and buttonbush (Cephalanthus occidentalis). The canopy is discontinuous (10-20% coverage) (Beever and Dryden, 1992), and the number of species throughout the hydric pine flatwoods of southwest Florida is high: There are 992 plant species, including 98 that are federally listed (Beever and Beever, 1994). The flatwoods also support extensive seasonal growth of algae, aquatic invertebrates, and vertebrates associated with standing water.

The soils of the pine flatwoods are hydric. Even though sandy, they show weak polychromatic features that are associated with extended flooding. However, the transition from the hydric zone to the mesic zone is difficult to identify

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

because the mesic zone itself can be inundated annually, but for a shorter interval, and because the lenses of nonhydric soils, reflecting minor variations in topography, can be intermixed with a background of hydric soils.

The hydric pine flatwoods have in the past been viewed as a successional transition to other ecosystem types (Duever et al., 1976). Now, however, they are believed to be highly stable under natural conditions (Beever and Beever, 1994). Natural stability is undermined by anthropogenic change in hydrology, fire, or grazing, all of which are important factors in maintaining the hydric pine flatwoods.

The seasonally dry condition of hydric pine flatwoods allows the vegetation to burn. In pre-Columbian times, burning probably occurred every 3-10 years (Beever and Beever, 1994) and was apparently patchy in its distribution so that the combustion chronologies, and therefore the plant community successional stages reflecting response to burning, made a mosaic on the landscape. Suppression of fire causes extensive vegetational change because the understory becomes predominated by the growth of plants that are eliminated or continually suppressed by frequent fire. In addition, accumulation of fuel in the understory over long periods ultimately could sustain a canopy fire that could damage or eliminate slash pine, which is tolerant of understory fires. Excessively frequent fire also can cause change in understory vegetation.

The delineation of boundaries for hydric pine flatwood is difficult. The interior of the hydric zone shows many diagnostic features of wetland status, including dried algal mats, remains of aquatic invertebrates, hydrophytic vegetation, and hydric soils. However, the margin of the hydric zone intergrades with the mesic area so subtly that it is difficult to find a line of demarcation (Figure B4.1). In some instances, the transition extends for miles, over which mesic islands interdigitate with hydric zones. Careful analysis of the soil could show the boundaries, but is impractical over large distances because of the extensive subsurface data collection that would be required. In practice, the most useful indicator is upland vegetation at the understory level, particularly the saw palmetto (Serenoa repens), which tends to come to the margin of the transition zone. However, heavy reliance on a single indicator could produce errors that could be avoided by more extensive analysis.

References

Abrahamson, W.G., and D.C. Hartnett. 1990. Pine flatwoods and dry prairies. Pp. 103-149 in R.L. Myers and I.I. Ewel, eds. Ecosystems of Florida. Univ. Central Florida Press.


Beever, J.W. III, and L.B. Beever. 1994. The effects of annual burning on the understory of a hydric slash pine flatwoods in southwest Florida (manuscript).

Beever, J.W. III, and K.A. Dryden. 1992. Red-cockaded woodpeckers and hydric slash pine flatwoods. Trans. 57th N.A. Wildl. and Nat. Res. Conf. 693-700.

Birnhak, B.I., and J.P. Crowder. 1974. An evaluation of the extent of vegetative habitat alteration in

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

south Florida 1943-1970. South Florida Environ. Prot. Ecol. Rep. DI-SFEP-74-22. USDI. 22 pp.

Duever, M.J., J.E. Carlson, L.H. Gunderson, and L.C. Duever. 1976. Corkscrew Swamp, a virgin strand, ecosystems analysis at Corkscrew Swamp. Pp. 707-737 in H.T. Odum (ed.). Cypress Wetlands. 3rd Ann. Rept. on Research Projects. Nov. 1875-Dec. 1976. Center for Wetlands, Univ. Florida, Gainesville.

CASE STUDY 5

Prairie Pothole Region, North Dakota Extreme Interannual Variation

The prairie pothole region, which extends from northwest Minnesota and Iowa across the Dakotas to Alberta (Figure B5.1), provides an excellent example of regionally distinctive wetlands that present special regulatory problems. The potholes, which are of glacial origin and lie on rolling till deposits, are a major landscape feature because of their abundance. Within the Dakotas alone, there are approximately 2.3 million that contain water at least temporarily (Kantrud et al., 1989). To the extent that they could be drained or filled, potholes could expand both the area of arable land and the convenience of farming, which is otherwise impeded by the necessity to circumnavigate these features in the culti-

FIGURE B5.1. Distribution of prairie potholes.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

vation of grains. Some potholes can be farmed in dry years without being drained, but most potholes cannot be farmed in wet years. Although drainage of potholes was practiced extensively in some parts of the Dakotas and Iowa before the enactment of wetland regulation, wetland regulatory determinations are now required. Some potholes are so shallow or small that they lack wetland features, but many are jurisdictional wetlands.

Although potholes are generally small, they have a wide range of physical characteristics. They have been divided into seven classes (Stewart and Kantrud, 1971). Class I potholes are designated ephemeral and are not wet with sufficient frequency to develop wetland soils or plants. Class II potholes are designated temporary. These often retain water for an extended period during the wet season, but can be dry or almost so in dry years. Seasonal potholes (Class III) retain water for a substantial period during the wet season in most years. Although semipermanent potholes (Class IV) almost always contain water, they can become dry in the driest season of the driest years, and the amount of water can vary substantially between years or between seasons. Permanent potholes (Class V) always contain water. Class VI includes alkaline basins that are wet only intermittently, and Class VII is for fens maintained by seepage. Classes III and IV are most common, Classes I and II are common, and the other classes are less abundant.

Precipitation comes to the North Dakota pothole region primarily in the spring and summer, and June is the wettest month (Kantrud et al., 1989), although potholes also can receive a substantial amount of water as a result of snowmelt after winters when snow accumulation is substantial. The seasonal sequence of events can differ for different classes of potholes. For example, the shallowest potholes thaw before the deepest ones and retain water readily over an ice seal in the soil below the wetland. Deeper potholes thaw later. Such variation in physical properties of potholes could be of considerable functional significance. For example, the potholes that thaw first are the only ones available to waterfowl that arrive early in the year.

Ground water plays an important role in sustaining the prairie potholes. The potholes can be divided roughly into three hydrologic categories: recharge, throughflow, and discharge. The recharge areas lie above ground water; they accumulate surface water (mostly from runoff fed by snowmelt) that subsequently recharges underlying ground water, The throughflow basins receive seepage from ground water, but also lose water back to the ground water pool on the lower end of the ground water gradient. The discharge basins receive upwelling ground water seepage and lost water mainly by evapotranspiration.

Hydrologic regimes affect the chemistry of potholes (LaBaugh et al., 1987; LaBaugh, 1989). Most potholes are at least moderately saline, but discharge potholes become highly saline. Saline conditions are often marked by a ring of salt deposits around the margin of the basin. The more saline potholes can have a distinctive vegetation and aquatic fauna (Kantrud et al. 1989). These basins

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

often cannot be used for agricultural purposes, even if they are drained, because of the concentration of salts in the sediments above the tolerance of most crops.

The prairie potholes support a variety of herbaceous vegetation, but are usually without woody plants. The community composition of vascular plants is typically graded in concentric rings from the center or low-water mark of the pothole to a few feet above the mean high water-mark (Figure B5.2). The gradation reflects degrees of tolerance or competitive ability for individual plant species as a function of the duration and frequency of inundation.

Invertebrate fauna of the prairie potholes is diverse and abundant. It includes such taxa as the phantom midge (Chaoborus) and other dipteran larvae, odonates, cladocerans, ostracods, and many others. Large invertebrates tend to be especially abundant in the potholes because very few of the potholes contain fish. The fathead minnow (Pimephales promelas) is present in some of the Class V potholes, and some artificially deepened potholes have been stocked with game fish. However, the pothole waters are predominantly fishless and therefore support large populations of microinvertebrates that would otherwise be eliminated or reduced by fish.

The prairie potholes are famed for their support of waterfowl and wading birds; as much as half the waterfowl of North America originate from the pothole

FIGURE B5.2a The vegetation of a Class V (permanent) pothole,  showing zonation. Source: Brinson, 1993.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B5.2b Representative zonation of hydrology in a prairie pothole. Source: Brinson, 1993.

region (Kantrud et al., 1989). Because of the high ratio of shoreline to surface area associated with these small bodies of water, the total area of shoreline available for waterfowl nesting is extremely large, and invertebrate populations provide abundant food. Less obvious but equally important is the role of potholes in ground water recharge and hydrologic buffering (Winter, 1989).

Prairie potholes that are farmed in dry years qualify as farmed wetlands under the Food Security Act of 1985. Fanning often results in simplification of plant communities by cultivation, impairment of natural biodiversity by the use of herbicides, and physical disturbance (siltation, furrowing).

The soils of the entire prairie pothole region are characteristically dark. The pothole wetlands are underlain by hydric soils that are distinct, however, from the adjacent upland soils (Richardson et al., 1994). Careful examination of soils in the zone of frequent inundation shows the distinctive chroma and redoximorphic features that cannot be found on uplands.

Classification of the prairie potholes is a point of major practical concern, but delineation of pothole boundaries is far less so. Class I potholes (ephemeral potholes) are not considered jurisdictional wetlands and can be drained, filled, or cultivated without restriction by the Food Security Act of 1985. Other classes cannot be drained or filled. Therefore, the boundary between Class I and Class H and the validity of the typology are subject to scrutiny by agricultural landholders who could benefit economically from draining or filling, especially of shallow,

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

nonsaline potholes. Because the intended use is agricultural rather than commercial or residential, the exact margin of a given pothole is of much less concern than is the legality of draining or filling for agricultural use.

The major complication in evaluating prairie potholes in relation to the regulatory guidance on wetland identification derives from the extreme hydrologic variability in the prairie pothole region. As shown in Figure B5.3, the amount of precipitation varies greatly, such that individual potholes can be deeply inundated for many weeks in the wettest years and barely moist at the surface in the driest years. To complicate matters further, both the vegetation and the invertebrate fauna of the potholes are adapted to widely varying hydrologic conditions. Thus, a pothole that appears to lack the biotic characteristics of a wetland in the driest years can in wet years have animal and plant communities that are clearly associated with wetlands.

Even a statistical analysis of the hydrologic irregularities in the pothole region is difficult because the inter year variability is neither random nor regular. There appears to be a certain amount of contagion in the hydrologic data base, suggestive of drought cycles running to a decade or more, but it is also possible to see some of the driest and some of the wettest conditions in two consecutive years (Figure B5.3). Thus, even with hydrologic records, it is difficult to compute reliably the recurrence, frequency, duration, and depth of inundation for individual potholes. Because of the high variability of vegetation, aquatic life, and hydrology over the short term, hydric soils are a particularly important indicator of wetland status in the prairie pothole region.

References

Brinson, M. M. 1993a. A hydrogeomorphic classification for wetlands. Wetlands Research Program Technical Report WRP-DE-4. U.S. Army Corps of Engineers, Waterway Experiment Station. Vicksburg, MS: Bridgham and Richardson.


Kantrud, H.A., G.L. Krapu, and G.A. Swanson. 1989. Prairie Basin Wetlands of the Dakotas: A Community Profile. U.S. Fish and Wildlife Service Biological Report 85 (7.28). 116 p.


LaBaugh, J.W. 1989. Chemical characteristics of water in wetlands and lakes in the Northern Prairie of North America. Pp. 56-90 in A.G. van der Valk (ed.). Northern Prairie Wetlands. Iowa State University Press, Ames, IA.

LaBaugh, J.W., T.C. Winter, V.A. Adomaitis, and G.A. Swanson. 1987. Hydrology and chemistry of selected prairie wetlands in the Cottonwood Lake area, Stutsman County, North Dakota, 1979-82. U.S. Geol. Surv. Prof. Pap. 1431.26 p.


Richardson, J.L., J.L. Arndt, and J. Freeland. 1994. Wetland soils of the prairie potholes. Advances in Agronomy 52:121-171.


Stewart, R.E., and H.A. Kantrud. 1971. Classification of natural ponds and lakes in the glaciated prairie region. Bureau of Sport Fisheries and Wildlife Resource Publication 92. 56 pp.


Winter, T.C. 1989. Hydrologic studies of wetlands in the northern prairie. Pp. 16-54 in A.G. Van der Valk, ed. Northern Prairie Wetlands. Iowa State University Press, Ames, IA.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

FIGURE B5.3 Long-term hydrologic record from the prairie pothole region reconstructed from historical records and tree ring data.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

APPENDIX
C

Glossary


abiotic

nonliving (usually refers to substances or environmental factors).

adventitious root

root that grows from plant parts other than the primary root. Often develop in flood-tolerant and flood-intolerant plants just above the anaerobic zone when the plants are flooded; can develop when plants are engulfed by sediment or moss.

aerenchyma

tissue with numerous large intercellular spaces; common in the roots and stems of many aquatic and wetland plants. Facilitates oxygenation of the roots and allows plants to survive in saturated and inundated soils.

aerobic

growing or proceeding only in the presence of rice oxygen, as in aerobic respiration. Living, active, or occurring only in the presence of oxygen.

aggradation

deposition of alluvial materials resulting in increased elevations. In permafrost, it is a rise in the permafrost table.

alluvium

sediment deposited by flowing water, as in a river bed, floodplain, or delta.

altered wetland

area affected by anthropogenic or natural events, such that one or more indicators of relative wetland character is absent, obscured, or provides information no longer representative of original condition.

anaerobic

growing in the absence of molecular oxygen, as in aerobic bacteria. Occurring in the absence of molecular of oxygen, as in biochemical processes.

anoxic

absence of molecular oxygen.

aquic soil

soil that currently experiences continuous or periodic saturation and reduction. Presence indicated by redoximorphic features and verified by measuring saturation and reduction, except in artificially drained soils.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

artificial drainagere

oval of free water from soil by surface mounding, ditches, or subsurface tiles to the extent that water table levels are changed significantly in connection with specific land uses.

artificial wetland

wetland constructed where one did not exist before.


bajada

broad alluvial slope extending from the base of a mountain range out into a basin, formed by coalescence of separate alluvial fans.

biogeographic region

any region delineated by its biological and geographic characteristics.

bog

a nutrient-poor, acidic-peat-accumulating wetland. Used in the restrictive sense to refer to those peatlands that receive all of their water from rain and snow—ombrotrophic bogs. Also used for any nutrient-poor, acidic peatland with a distinctive plant community of peat mosses (Sphagnum spp.), ericaceous shrubs, and sedges or coniferous trees. This broader use of the term thus includes weakly minerotrophic peatlands—poor fens.

bosque

dense growth of trees and underbrush, normally applied to arid riparian zone.

bryophyte

nonvascular plant, composed of moss and liverwort or hornwort (or hepatics). Inhabits a range of habitats from dry, barren rocks to submerged objects, but most frequent where an abundance of moisture is assured. Some bryophyte species are the dominant vegetation in bogs and poor fens.


categorize

to put into any of several fundamental and distinct classes to which entities or concepts belong. A category is a division within a system of classification.

chroma

the relative purity of saturation of a color. The intensity of distinctive hue as related to greyness. One of the three variables of color.

cienega

swamp or marsh in the southwestern U.S., especially one formed and fed by streams or ground water discharge.

classify

to assign to a category.

converted wetland

see prior convened wetland.

criterion

a standard on which a judgment or decision may be based.


depressional wetland

wetland occurring in a depression in the landscape so that the catchment area for surface runoff is generally small.

disturbed area

area where vegetation, soil, or hydrology have been significantly altered, making a wetland determination difficult.


ecoregion

ecological region that has broad similarities to other regions with respect to soil, relief, and dominant vegetation.

ecotype

genetically distinct populations within a species that are adapted to the local conditions

edaphic

related to chemical and physical soil conditions, not including climate.

eluvial

the removal of soil material in suspension from a layer or layers of soil.

Entisol

mineral soil of slight or recent development. An order of the USDA soil taxonomy.

epipedon

cliagnostic horizon formed at the soil surface, used in the classifica-

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

tion of soils. Properties should be determined after mixing the surface soil to a depth of 7.02 in (18 cm), or the whole soil if its depth to bedrock is less than 7.02 in (18 cm).

ericaceous

of, relating to, or being a heath (shrubby evergreen) or of the heath family Ericacea.

eutrophication

process by which a body of water becomes highly productive either naturally or by pollution rich in dissolved nutrients (such as phosphates). Eutrophic lakes are often shallow, with a seasonal deficiency in dissolved oxygen.

evapotranspiration

loss of water from the soil both by evaporation and by transpiration of the water from the plants growing thereon.


facultative species

plant species that do not always occur in wetlands. One of five indicator categories used in determining whether the vegetation of a site is or is not hydrophytic. Facultative (FAC) species have a similar probability of occurring in wetlands and nonwetland sites. Facultative-wet (FACW) species have a higher probability of occurring in wetlands than in nonwetland sites. Facultative-upland (FACU) species have a higher probability of occurring in nonwetland sites than in wetlands.

farmed wetland

area in which fanning is compatible with wetland status.

fen

minerotrophic, peat-accumulating wetland. Includes all peatlands that receive water that has been in contact with mineral soils, in contrast to ombrotrophic bogs, which receive only rainwater and snow. Includes both weakly minerotrophic peatlands (poor fens) that are acidic and strongly minerotrophic peatlands (rich fens) that are alkaline. Fens support a range of vegetation types, including sedge and moss-dominated communities and coniferous forest.

Folist

Histosol derived from leaf litter.

fringe wetland

wetland near a large body of water, most typically the ocean, that receives frequent and regular two-way flow from astronomic tides or wind-driven fluctuations in water-level.


geomorphology

study of characteristics, origin, and development of land forms.

gleyed

soil developed under conditions of poor drainage, resulting in reduction of. iron and other elements, manifested by the presence of neutral grey, bluish, or greenish colors as reduced matrix or redox depletions (see Appendix A).


Histosol

soil that has organic materials in more than half of the upper 32 in (80 cm) or of any thickness if overlying bedrock. Formed almost exclusively in wetlands. An order of the USDA soil taxonomy.

hydric soil

soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic, conditions in the upper part (1991 National Technical Committee on Hydric Soils definition).

hydrogeomorphic

of or pertaining to a synthesis of the geomorphic setting, the water source and its transport, and hydrodynamics.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

hydromorphic

used to describe a wetland classification method based on position in the landscape, water sources, and factors that control the velocity of the water as it passes through the wetland.

hydroperiod

depth, duration, seasonality, and frequency of flooding.

hydrophyte

any plant growing in water or on a substrate that is at least periodically deficient in oxygen as a result of excessive water. Plants typically found in wetland habitats.


illuvial horizon

soil layer or horizon in which material carried from an overlaying layer has been precipitated from solution or deposited from suspension.

indicator

organism, ecological community, or structural feature so strictly associated with a particular environmental condition that its presence indicates the existence of the condition.

isolated wetland

wetland not adjacent to another body of water.


landscape ecology

specialty that deals with the patterns and processes of biological systems in spatially and temporally heterogeneous environments at the scale of landscapes, i.e., generally hundreds to tens of thousands of acres.

landscape perspective

method of viewing the interactive parts of a geographic area that are not necessarily all within a single watershed.

lenticel

pore in the stem of a woody plant through which gases are exchanged between the atmosphere and stem tissues.

lotic

pertaining to or living in flowing water.

lysimeter

device for measuring the percolation of water through soils and for determining the soluble constituents removed in the percolate.


marsh

wetland characterized by frequent or continual inundation, emergent herbaceous vegetation such as cattails and rushes, and mineral soils.

mesocosm

in aquatic biology, an artificial system used for study that is larger than typical aquaria and smaller than lakes.

mire

peat-accumulating wetland (European definition).

Mollisol

soil common to the world's grasslands, characterized by a dark surface layer rich in organic matter. An order of the USDA soil taxonomy.

monotypic

being the only representative of its group, or more commonly, having only one type, e.g., a genus or plant community consisting of a single species.

morphology

branch of biology that deals with form and structure; also form and structure of an organism or any of its parts, or of soil.


obligate wetland species

plant species that almost always occur in wetlands. One of five indicator categories used in determining whether the vegetation of a site is hydrophytic.

offsite determination method

a technique for making a wetland determination in the office.

ombrotrophic bog

peatland that receives precipitation as the sole source of water. Generally peat has accumulated enough to isolate the plants from

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

acquiring nutrients from the underlying mineral strata. The elevated surface is indicative of tertiary mines.

onsite determination method

a technique for making a wetland determination in the field.

opportunity cost

in economics, the cost in lost opportunity or flexibility of investing a resource (usually money or time) in a particular instrument or project, thus making the resource unavailable for other investments.

oxic

xygenated.

oxidized rhizosphere

precipitation of yellowish-red ferric compounds around the roots and rhizomes of plants growing in frequently saturated soils that otherwise exhibit a reduced matrix. Caused by the transport of oxygen from leaves to roots and rhizomes through a system of air-filled pore space in plant tissue (aerenchyma).

Oxisol

thick, weathered soil of the humid tropics, largely depleted in the minerals that promote fertility. An order of the USDA soil taxonomy.


paludification

landscape phenomenon of the accumulation of organic matter on a mineral soil thus forming a Histosol. One process by which a peatland forms through the waterlogging of formerly terrestrial or upland habitats.

panchromatic

sensitive to light of all colors in the visible spectrum.

parameter

originally mathematics, often used more broadly. In this report, either a quantity or a constant whose value varies with the circumstances of its application (e.g., the radius of a circle), or a set of properties (usually physical) whose values determine the characteristics or behavior of something (e.g., atmospheric parameters, wetland parameters).

peat

deposit of partially decomposed or undecomposed plant material, or both. Can contain the remains of mosses, sedges, and other herbaceous plants or of trees and shrubs. Accumulates only in places that are sufficiently wet to prevent decomposition from keeping pace with the production of organic matter.

peatlands

generic term used to refer to all peat-accumulating wetlands—bogs and fens.

phreatophyte

plant that has a well-developed, deep root system that allows it to extract water from the permanent water-table (phreatic zone).

playa lake

shallow depression similar to a prairie pothole, abundant on the Southern High Plains on a tableland south of the Canadian River in Texas and New Mexico, characterized by annual or multiyear cycles of dry down and filling.

pneumatophore

specialized root formed on several species of plants occurring in frequently inundated habitats. The root is erect and protrudes above the soil surface. In some species promote root aeration in water-logged habitats.

pocosin

upland swamp of the coastal plain of the southeastern U.S.

prairie pothole

shallow, marshlike pond, particularly as found in the Dakotas and central Canadian provinces.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

prevalence index—weighted

average. A single number that summarizes quantitative data about a large number of species within a community and gives weight to each species' contribution to the final number in terms of an assigned value.

prior converted wetland

wetland converted to farmable land before Dec. 23, 1985.

propagule

structure of an organism involved in dispersal and reproduction, as in the seeds or spores of plants.

pulse-subsidy concept

the addition of nutrients in short intervals along with flooding.


redox potential

oxygen-reduction potential. A measure of the electron pressure (or availability) in a solution. Often used to quantify the degree of electrochemical reduction of wetland soils under anoxic conditions.

regionalize

to divide into regions or administrative districts.

restoration

return of an ecosystem to a close approximation of its condition prior to disturbance.

riparian ecosystem

ecosystem that has a high water table because of its proximity to an aquatic ecosystem or to subsurface water. Usually occurs as an ecotone between aquatic and upland ecosystems, but with distinctive vegetation and soils. Aridity, topographic relief, and presence of depositional soils most strongly influence the extent of high water tables and associated riparian ecosystems. Most commonly recognized as bottomland hardwood and floodplain forests in the eastern and central United States and as bosque or streambank vegetation in the West. Characterized by the combination of high species diversity, density, and productivity. Continuous interactions occur between riparian, aquatic, and upland terrestrial ecosystems through exchanges of energy, nutrients, and species.

riparian vegetation

vegetation growing close enough to a lake or river that its annual evapotranspiration is a factor in the lake or river regimen.

riverine wetland

wetland system of less than 0.5 ppt ocean salts, exposed to channelized flow regimes. Categorized according to flow regimes such as tidal waters, slow-moving waters with well-developed floodplains, fast-moving waters with little floodplain, and intermittent systems.


saturation

condition in which all pore spaces are filled with water to the exclusion of a gaseous phase.

soil matrix

the portion of a given soil that has the dominant color. In most cases, the portion of the soil that has more than 50% of the same color.

spodic horizon

mineral soil horizon characterized by the illuvial accumulation of aluminum and organic carbon with or without iron.

Spodosol

mineral soil that has a spodic horizon. An order of the USDA soil taxonomy.

swamp

emergent wetland in which the uppermost stratum of vegetation is composed primarily of trees.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

thermokarst

topography created by the thawing of ice-rich permafrost and characterized by a complex, uneven ground surface that includes mounds, sink holes, tunnels, caverns, short ravines, lake basins, and circular lowlands. Occurs in unconsolidated materials, often loess.

tidal marsh

saltwater or brackish wetland dominated by herbaceous vegetation and subject to tidal flow. Can be flooded regularly (elevations low enough to be inundated by nearly all tides) or irregularly (too isolated to be inundated by all tides).

tidal subsidy

augmentation or support of water tables by tidal fluctuations; the way in which nutrients are added and toxic materials removed from areas of greater tidal energy.


vernal pool

shallow, intermittently flooded wet meadow, generally covered by water for extended periods during the cool season but dry for most of the summer. Used most frequently to refer to such habitats in the Mediterranean climate region of the Pacific coast.

Vertisol

clay-rich soil in which deep cracks form in the dry season. An order of the USDA soil taxonomy.


water budget

balance between the inflows and outflows of water.

watershed

surface drainage area that contributes water to a lake or river.

wet meadow

any type of wetland dominated by herbaceous vegetation (frequently sedges of the genus Carex) and with waterlogged soil near the surface but without standing water for most of the year.

wetland mitigation

the practice of allowing unavoidable losses of wetland in exchange for their replacement elsewhere through restoration or through creation of new wetlands.

wet prairie

herbaceous wetland dominated by grasses rather than sedges and with waterlogged soil near the surface but without standing water for most of the year.


zonation

state or condition of being marked with bands, as of color or texture. Wetland vegetation often exhibits distinct zones characterized by plant communities composed of different species.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

APPENDIX
D

Committee on Wetlands Characterization Biographical Sketches

WILLIAM M. LEWIS, JR.M, Chair is Professor, Department of Environmental, Population, and Organismic Biology at the University of Colorado, Boulder, and also serves as Director of the Center for Limnology at CU-Boulder. Professor Lewis received his Ph.D. degree in 1974 at Indiana University with emphasis on limnology, the study of inland waters. His research interests, as reflected by over 120 journal articles and books, include productivity and other metabolic aspects of aquatic ecosystems, aquatic food webs, composition of biotic communities, nutrient cycling, and the quality of inland waters. The geographic extent of Professor Lewis's work encompasses not only the montane and plains areas of Colorado, but also Latin America and southeast Asia, where he has conducted extensive studies of tropical aquatic systems. Professor Lewis has served on the National Research Council Committee on Irrigation-Induced Water Quality Problems and is currently Chair of the NRC's Glen Canyon Environmental Studies Committee. He is also a member of the NRC's Water Science and Technology Board. Professor Lewis is currently a member of the Natural Resources Law Center Advisory Board.

BARBARA LYNN BEDFORD received her B.A. from Marquette University in theology, her M.S. and Ph.D. in land resources from the University of Wisconsin-Madison. She is presently an assistant professor in the Department of Natural Resources at Cornell University. For ten years (1980-1990) she was Associate Director, and for a year (1991) the Director, of the Ecosystems Research Center of Excellence at Cornell University. She is a wetlands consultant to EPA's Science Advisory Board and recently served as a member of the Man-

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

agement Advisory Group to the Assistant Administrator for Water at EPA. Prior to assuming her academic positions, she worked with local and state government agencies, in wetlands mapping inventory, classification and development of wetlands regulations. Her research includes plant ecology of freshwater ecosystems; application of ecological knowledge to environmental assessment, regulation and management; response of wetland plants and communities to changes in hydrology and nutrient loading; and influence of plant species on wetland ecosystem processes.

FRED P. BOSSELMAN is currently professor of Law, Chicago-Kent College of Law. His areas of research include land use planning. He received his B.A. from the University of Colorado, Boulder, and his J.D. from Harvard Law School. He is a member of the Board of Advisors of the American Law Institute's Restatement of Property and the Board of Directors of the Sonoran Institute, on the editorial boards of the Land Use and Environmental Law Reporters, the Practical Real Estate Lawyer, and the Land Use Law and Zoning Digest. He is co-chair of the annual Land Use Institute sponsored by the ALI-ABA Committee on Continuing Legal Education. He is past president of the American Planning Association, past assistant chair of the National Policy Council of the Urban Land Institute, and was a member of the Board of Directors of the National Audubon Society and the American Society of Planning Officials.

MARK M. BRINSON received his B.S. from Heidelberg College, his M.S. from University of Michigan, Ann Arbor, and his Ph.D. (botany) from the University of Florida. He is currently Professor of biology at East Carolina University. He spent 1 year as an ecologist with the Office of Biological Services at the U.S. Fish and Wildlife Service. He provided testimony before the congressional committees on the functioning of wetlands and delineation issues. He has worked on the cycling of nitrogen, phosphorus and carbon in swamp forests, estuaries and marshes. Current research deals with the response of coastal wetlands to rising sea level. He is working on functional assessment of wetlands based on reference wetlands as scalars.

PAUL ALLEN GARRETT is an Ecologist with the Federal Highway Administration (FHWA). He received his B.S. in biology from Memphis State University and his M.S. in zoology and Ph.D. in botany from Montana State University. He has participated as senior biologist with several projects involving wetlands identification, classification, and functional analysis. He presently is involved in developing and administering. wetland research programs for FHWA, as well as serving on the interagency group on Federal Wetlands Policy.

CONSTANCE HUNT received her B.S. in wildlife biology from Arizona State University, and her M.A. in public policy from the University of Chicago. She is a senior program officer with the World Wildlife Fund, where she is responsible for the management of programs to promote wetland restoration and

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

conservation of biodiversity on private lands (1993-). From 1990-1993, she was program manager and coordinator for Lakewide Management Plans of the U.S. Environmental Protection Agency, where she developed lakewide management programs for reducing pollution in the Great Lakes. From 1987-1990 she was a biologist with the U.S. Army Corps of Engineers, where she created, coordinated, and implemented intergovernmental conservation plans for stream basins and wetland complexes in accordance with section 404 of the Clean Water Act. She also performed wetland evaluations and delineations, permit processing, and environmental impact analysis.

CAROL A. JOHNSTON received her B.S. in natural resources from Cornell University, her M.S. in land resources and soil science from the University of Wisconsin, and her Ph.D. in soil science from the University of Wisconsin. Currently she is a Senior Research Associate with the Natural Resources Research Institute at the University of Minnesota. From 1978-1983 she directed the Wisconsin Wetlands Inventory for the Wisconsin Department of Natural Resources, and in 1989-1990 was a Research Ecologist with the Environmental Protection Agency. Dr. Johnston is currently a member of the NRC Water Science and Technology Board. Her research interests include wetland soils, biogeochemistry, and mapping; effects of land/water interactions on surface water quantity and quality, spatial and temporal variability of wetland processes; and geographic information systems.

DOUGLAS L. KANE received his B.S. in civil engineering and M.S. in civil engineering and water management from the University of Wisconsin, and his PhD in civil engineering from the University of Minnesota. Currently; he is director of the Water Research Center and a professor of water resources and civil engineering at the University of Alaska, Fairbanks. His research focuses on ground water hydrology, snow hydrology, hydraulics, water resources engineering, and cold regions hydrology.

A. MICHAEL MACRANDER received his B.A. from Tarkio College; spent two years of graduate work at Northern Arizona University, and received his Ph.D. from the University of Alabama. He is presently Senior Environmental Specialist at Corporate Environmental Affairs at Shell Oil Company. He is responsible for providing technical support and guidance on issues related to the identification and protection of sensitive ecological resources. He has specific responsibility for wetlands, threatened and endangered species, ecological risk assessment, and oil spill response. From 1983-1991 he was an Associate Researcher at the University of Alabama where he worked in the design and use of biological information systems including the Southwest Regional Floral Information System.

JAMES C. McCULLEY IV received his B.A. and M.S. in biology from Rutgers University. He is President of Environmental Consultants, Inc., a firm

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

specializing in wetland delineations, wetland permitting, wetland mitigation, wetland assessment, water quality studies, ground water monitoring, violation resolution, expert witness testimony, and natural resource studies, as well as other services. He has represented the Homebuilders Association of Delaware on several panels, including the Governor's Wetlands Steering Committee, the Governor's Freshwater Wetlands Roundtable, the New Castle County Executive's committee to formulate a wetlands policy. He advises the Homebuilders Association of Delaware on wetland and other environmental issues.

WILLIAM JOSEPH MITSCH received his B.S. from University of Notre Dame, his M.E. and his Ph.D. in environmental engineering science from University of Florida. Since 1986 he has been professor of natural resources and environmental science at Ohio State University. He previously taught at Illinois Institute of Technology and the University of Louisville. His research interests include wetland ecology and management; biogeochemical cycling; ecological engineering; ecological modelling; water quality role of wetlands; and energy flow in ecological and human systems. He has coauthored the textbook Wetlands, chaired the 1992 INTECOL conference on wetlands, serves on the editorial board of several journals and is editor-in-chief of Ecological Engineering.

WILLIAM H. PATRICK, JR. received his B.S., M.S. and his Ph.D. in soils science from Louisiana State University at Baton Rouge. He joined the faculty of Louisiana State University in 1953 where he has served as Boyd Professor of Marine Science since 1978. He received an honorary doctorate degree from Ghent University, Belgium, His research interests include physicochemical properties of and reactions in soils, particularly wetland soils.

ROGER A. POST received his B.S. in wildlife management from the University of Alaska-Fairbanks, and his M.S. in forest zoology from the SUNY College of Environmental Science and Forestry. He has worked in environmental consulting and governmental focusing on mitigation of impacts of large construction projects and currently is a habitat biologist with the Alaska Department of Fish and Game. As habitat biologist he published a report reviewing the functions, species-habitat relationships, and management of arctic wetlands, and is preparing a functional profile of black spruce wetlands in Alaska. He has prepared reports on restoration of Arctic-tundra wetlands, management of nonpoint-source pollution related to placer mining, and a restoration plan for a mined stream system.

DONALD L SIEGEL is a Professor of Geology at Syracuse University where he teaches graduate courses in hydrogeology and aqueous geochemistry. He holds B.S. and M.S. degrees in geology from the University of Rhode Island and Penn State University, respectively, and a Ph.D. in Hydrogeology from the University of Minnesota. His research interests are in solute transport at both local and regional scales, wetland-ground water interaction, and paleohydro-

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×

geology. He was a member of the NRC's Committee on Techniques for Assessing Ground Water Vulnerability.

RICHARD WAYNE SKAGGS received his B.S. and his M.S. in agricultural engineering from the University of Kentucky and his Ph.D. in agricultural engineering from Purdue University. He has served on the faculty in the Biological and Agricultural Engineering Department of North Carolina State University since 1984. Currently, he is the William Neal Reynolds Professor at NC State. His expertise is in agricultural drainage and related water management for poorly drained soils; hydrology of low relief and high water table watersheds. He has made scientific contributions in the development of computer simulation and mathematical models to quantify the performance of drainage and water table control systems. His current interests are in determining and developing methods to describe the effects of water management and farming practices on drainage water quality and hydrology; applying models to describe the hydrology of certain types of wetlands. He is a member of the National Academy of Engineering.

MARGARET (PEGGY) STRAND received her B.A. in history from the University of Rochester, her M.A. in history from the University of Rhode Island, and her J.D. from Marshall Wythe School of Law at the College of William and Mary. She is a partner with Bayh, Connaughton & Malone, P.C., Washington, DC, where she provides counsel on environmental compliance and conducts environmental litigation, focusing on EPA-administered regulatory programs. Prior to that, she was chief of the Environmental Defense Section of the US Department of Justice, where she was involved in environmental policy issues including wetlands regulation and enforcement. She serves on the editorial board of the Environmental Law Reporter and the Federal Facilities Environmental Compliance Journal. She is the author of Federal Wetlands Law, a primer published by the Environmental Law Institute in 1993. Ms. Strand is a member of the NRC Board on Environmental Studies and Toxicology.

JOY B. ZEDLER holds a Ph.D. in botany (plant ecology) from the University of Wisconsin. Since 1969, she has been at San Diego State University (SDSU) and is currently a professor of biology at SDSU and director of the Pacific Estuarine Research Laboratory. Her research interests include salt marsh ecology; structure and functioning of coastal wetlands; restoration and construction of wetland ecosystems, effects of rare, extreme events on estuarine ecosystems; dynamics of nutrients and algae in coastal wetlands; and use of scientific information in the management of coastal habitats. She helped develop the wetland research plan for the EPA and participated in the literature review on the status of wetland restoration. She was a member of the NRC's Committee on Restoration of Aquatic Ecosystems, and is a former member of the NRC's Water Science and Technology Board.

Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
This page in the original is blank.
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 253
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 254
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 255
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 256
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 257
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 258
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 259
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 260
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 261
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 262
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 263
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 264
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 265
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 266
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 267
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 268
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 269
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 270
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 271
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 272
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 273
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 274
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 275
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 276
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 277
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 278
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 279
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 280
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 281
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 282
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 283
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 284
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 285
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 286
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 287
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 288
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 289
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 290
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 291
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 292
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 293
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 294
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 295
Suggested Citation:"APPENDIXES." National Research Council. 1995. Wetlands: Characteristics and Boundaries. Washington, DC: The National Academies Press. doi: 10.17226/4766.
×
Page 296
Next: INDEX »
Wetlands: Characteristics and Boundaries Get This Book
×
Buy Paperback | $85.00 Buy Ebook | $69.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

"Wetlands" has become a hot word in the current environmental debate. But what does it signify? In 1991, proposed changes in the legal definities of wetlands stirred controversy and focused attention on the scientific and economic aspects of their management.

This volume explores how to define wetlands. The committee--whose members were drawn from academia, government, business, and the environmental community--builds a rational, scientific basis for delineating wetlands in the landscape and offers recommendations for further action.

Wetlands also discusses the diverse hydrological and ecological functions of wetlands, and makes recommendations concerning so-called controversial areas such as permafrost wetlands, riparian ecosystems, irregularly flooded sites, and agricultural wetlands. It presents criteria for identifying wetlands and explores the problems of applying those criteria when there are seasonal changes in water levels.

This comprehensive and practical volume will be of interest to environmental scientists and advocates, hydrologists, policymakers, regulators, faculty, researchers, and students of environmental studies.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!