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.



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Wetlands: Characteristics and Boundaries 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.

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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 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: 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. 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. 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. 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

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Wetlands: Characteristics and Boundaries 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. 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: Redox concentrations - These are zones of apparent accumulation of Fe-Mn (iron-manganese) oxides. 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. 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. 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:

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Wetlands: Characteristics and Boundaries 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): Floods frequent and irregular, so that any use of the soil for crops is too uncertain to be practicable. Floods frequent but occurring regularly during certain months of the year, so that the soil may be used for crops at other times. 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. 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.

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Wetlands: Characteristics and Boundaries 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.

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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

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

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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.

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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.

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Wetlands: Characteristics and Boundaries 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.

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Wetlands: Characteristics and Boundaries 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.

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Wetlands: Characteristics and Boundaries 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-

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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

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Wetlands: Characteristics and Boundaries 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-

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Wetlands: Characteristics and Boundaries 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.

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