United States Office of April 1988
Environmental Protection Wetland Protection Revised Interim
Agency A-104-F FINAL
Washington, DC 20460
Water
&EPA Wetland Identification
and Delineation Manual
VOLUME 1
Rationale, Wetland Parameters,
and Overview of Jurisdictional
Approach
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WETLAND IDENTIFICATION ADN DELINEATATION MANUAL VOL;.l AND VOL. 2
01
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WETLAND IDENTIFICATION
AND DELINEATION MANUAL
VOLUME I
RATIONALE, WETLAND PARAMETERS,
AND OVERVIEW OF JURISDICTIONAL APPROACH
by
William S. Sipple
Office of Wetlands Protection
Office of Water
U.S. Environmental Protection Agency
Washington, D.C. 20460
U.S. Environmental Protection Agenoy
Library, Room 2404 PM-211-A
401 M Street, S.W.
-Winston, DC 20-4 60
April ,1988
Revised Interim Final
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PREFACE
According to Corps of Engineers and Environmental Protection Agency
(EPA) regulations (33 CFR Section 328.3 and 40 CFR Section 230.3,
respectively), wetlands are . . areas that are inundated or saturated
by surface or ground water at a frequency and duration sufficient to
support, and that under normal circumstances do support, a prevalence
of vegetation typically adapted for life in saturated soil conditions.
Wetlands generally include swamps, marshes, bogs and similar areas."
Although this definition has been in effect since 1977, the development
of formal guidance for implementing it has been slow, despite the fact
that such guidance could help assure regional and national consistency
in making wetland jurisdictional determinations. Moreover, a consistent,
repeatable operational methodology for determining the presence and
boundaries of wetlands as defined under the federal regulations cited
above would alleviate some concerns of the regulated public and various
private interest groups; it would also substantially reduce interagency
^disputes over wetland jurisdictional determinations. Therefore, this
Wetland Identification and Delineation Manual was developed to address
the need for operational jurisdictional guidance.
EPA's Wetland Identification and Delineation Manual is comprised of two
volumes. Volume I presents EPA's rationale on wetland jurisdiction, elaborates
on the three wetland parameters generally considered when making wetland
jurisdictional determinations, and presents an overview of the jurisdictional
approaches developed by EPA in Volume II, the Field Methodology. Thus, it
lays the foundation for the three jurisdictional approaches presented in
Volume II.
The basic rationale behind EPA's wetland jurisdictional approach was
initially conceived in 1980 with the issuance of interim guidance for
identifying wetlands under the 404 program (Environmental Protection
Agency, 1980). In 1983 the rationale was expanded and a draft juris-
dictional approach was developed consistent with the revised rationale.
i 1 i
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EPA distributed the 1983 draft rationale and approach to about forty
potential peer reviewers. Because the responses were, for the most part,
favorable, additional revisions were made and a second draft was circulated
to about sixty potential peer reviewers 1n 1985. Individuals receiving
the drafts for review were associated with federal, state, and regional
governmental agencies, academic Institutions, consulting firms, and
private environmental organizations; they represented a wide range
of wetland technical expertise. The 1985 draft also went through EPA
regional review, as well as formal Interagency review by the U.S. F1sh
and Wildlife Service, Corps of Engineers, National Marine Fisheries Service,
and Soil Conservation Service. Based upon the 1985 peer review comments,
the comments from the federal agencies, and subsequent EPA field testing 1n
Arkansas, Illinois, Louisiana, Mississippi, Virginia (bottomland hardwoods),
North Carolina (pocosins), Maryland and Virginia (marshes and forested swamps),
an interim final Wetland Identification and Delineation Manual was developed.
The interim final Manual was field tested again during 1987 in Idaho (riparian
forests, shrub swamps, montane wet meadows, and bogs), Iowa (forested swamps
and marshes), Louisiana (fresh, brackish and saline tidal marshes), Maryland
(forested swamps and fresh tidal marshes), Massachusetts (wet meadows, bogs
and forested swamps), Texas (bottomland hardwoods) and Washington (forested
wetlands, wet meadows and bogs). Based upon the 1987 field testing, peer
review comments and comments from EPA regional offices, the Manual was further
revised where appropriate. Although the rationale and technical criteria
remain essentially the same, a number of procedural Improvements have been
i
made to both the simple and detailed approaches and a new approach for dealing
with atypical situations and/or normally variable environmental conditions
has been added. A more detailed explanation of these most recent revisions
can be found in a report on the field testing effort (Slpple, 1988). During
this same review period, the Corps of Engineers conducted field review of
its wetland delineation manual (Environmental Laboratory, 1987). Now that
their reviews are complete, both agencies plan to meet, consider the comments
received, and attempt to merge the two documents into one 404 wetland juris-
dictional methodology for use by both agencies.
iv
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The author truly appreciates the efforts of the many peer reviewers who
commented on the 1987 Interim final Manual or earlier drafts, Including Greg
Auble, Barbara Bedford, Virginia Carter, Harold Cassell, Lew Cowardln, Bill
Davis, Dave Davis, Doug Davis, Frank Dawson, M1ke Gantt, Cathy Garra, M1ke
Gilbert, Frank Golet, Dave Hardin, Robin Hart, John Hefner, Wayne Klockner,
Bill Kruczynskl, Lyndon Lee, D1ck Macomber, Gene McColllgan, Ken Metsler,
John Organ, Greg Peck, Don Reed, Charlie Rhodes, Charley Roman, Dana Sanders,
Bill Sanvllle, Hank Sather, J1m Schmld, Joe Shlsler, Pat Stuber, Carl Thomas,
Doug Thompson, Ralph T1ner, Fred Welnmann, and Bill W1len. Their many con-
structive comments and recommendations have been very helpful 1n refining
this document. EPA also appreciates the help of Its Regional Bottomland
Hardwood Wetland Delineation Review Team (Tom Glatzel, Lyndon Lee, Randy
Pomponio, Susan Ray, Charlie Rhodes, Bill Sipple, Norm Thomas, and Tom Welborn)
1n field testing the basic rationale underlying the Field Methodology at a
number of bottomland hardwood sites in 1986. The vegetation sampling protocol
1n the Field Methodology 1s to a large extent an outgrowth of that effort.
In addition, the 1987 field testing could not have been accomplished without
the aid of various agency and non-agency personnel, including Bob Barber,
Susan Bitter, John Bruza, Steve Caicco, Tom Davidson, Alex Dolgas, Ronnie
Duke, Woody Francis, M1ke Hollins, Bill Jenkins, Gene Keepper, Mark Kern,
Kathy Kunz, Bob Mosley, Tom Nystrom, Jeanene Peckham, Charlie Rhodes, Matt
Schwelsberg, Norm Sears, Eric See, Rod Schwarm, Ellaine Somers, Michele
Stevens, Rusty Swafford, Ralph T1ner and Gary Voerman. I certainly appreciate
all of their help. Helpful review and administrative guidance was provided
by Suzanne Schwartz, John Meagher, and Dave Davis of EPA's Office of Wetlands
Protection. Comments and suggestions received during the federal Interagency
review in 1985 were also instrumental in further refining the manual. In
fact, in addressing the soil and hydrology parameters In this manual 1n
1987, the author relied heavily upon materials already developed by the
Corps of Engineers in their wetland delineation manual cited above. Blake
Parker's review of the soil sections of the current version of the Manual
was also very helpful. Stan Franczak ably handled the huge typing load
associated with the 1987 and current versions of the Manual, as well as
the earlier drafts.
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TABLE OF CONTENTS
Paae
Section I. Introduction 1
Section II. Rationale 3
Section III. The Three Parameters: Hydrophytlc Vegetation, Hydrlc
Soils, and Wetland Hydrology 5
A. Hydrophytic Vegetation 5
B. Hydric Soils 10
C. Wetland Hydrology 15
Section IV. Overview of the Jurisdictional Approaches 21
A. General 21
B. Basic Steps for the Simple and Detailed Jurisdictional
Approaches 22
Section V. Literature Cited 29
Appendix A. Glossary A1
vi 1
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SECTION I: INTRODUCTION
This volume of the Wetland Identification and Delineation Manual was
developed as a companion document to Volume II, the Field Methodology. It
presents EPA's rationale on wetland jurisdiction (Section II), elaborates
on the three parameters generally considered in making wetland jurisdictional
determinations (Section III), and presents an overview of the jurisdictional
approaches developed by EPA in Volume II, the Field Methodology (Section IV).
Anyone using the Field Methodology, should first become familiar with
Volume I, since it lays the foundation for the jurisdictional approaches
presented in Volume II. Thus, Volume I should be thought of, in part, as
a prerequisite training document on the use of the Field Methodology. It
is particularly important to thoroughly review the glossary in Appendix A,
since a good understanding of the terms used in the methodology is imperative.
In utilizing this Field Identification and Delineation Manual, keep 1n
mind that wetland jurisdictional determinations frequently have both technical
and administrative components. Sometimes the latter component will play an
important role in jurisdictional determinations. For example, whether or
not an isolated wetland meets the commerce test and is thus a "water of the
United States" is beyond the scope of this document. Therefore, to the
extent practicable, this Wetland Identification and Delineation Manual
emphasizes the technical aspects of jurisdiction.
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SECTION II: RATIONALE
Although the three parameters mentioned in the Corps-EPA regulatory
definition of wetlands (vegetation, soils and hydrology) are determinative
factors in terms of whether or not a site is a wetland, it does not follow
that all three parameters have to be evaluated or measured in every instance
in order to determine the presence and boundaries of a wetland. Frequently,
vegetation alone, which is a reflection of hydrologic and soil conditions,
will suffice. Specifically, in the presence of one or more dominant obligate
wetland species and in the absence of significant hydrologic modifications,
it can be assumed that soils would, with some exceptions (e.g., where
obligate wetland plants have recently become established, but hydric soils
have not yet developed), be hydric and that wetland hydrology would be
present. In other words, there is generally no need to collect data on
soils and hydrology in a vegetation unit dominated by one or more obligate
wetland plant species. Likewise, there is generally no need to collect
soils and hydrology data for a vegetation unit dominated by one or more
obligate upland species. However, if vegetation alone is not diagnostic,
such as when only facultative species occur, soils and hydrology must be
considered in determining the extent of wetlands and/or uplands at a site.
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SECTION III: THE THREE WETLAND PARAMETERS: HYDROPHYTIC
VEGETATION, HYDRIC SOILS, AND WETLAND HYDROLOGY
A. Hydrophytic Vegetation
1. Characteristics of Hydrophytic Vegetation
As used in this manual, "hydrophyte" is a broad term that includes
both aquatic plants and wetland plants. Therefore, hydrophytic vegetation
includes any macroscopic plant life growing in water or on a substrate
that is a least periodically deficient of oxygen as a result of excessive
water content. Aquatic habitats are areas, other than wetlands, that
generally have shallow or deep water, which is either intermittently or
permanently present. Shallow water areas sometimes support non-emergent
macroscopic hydrophytes (e.g., submerged aquatic, unattached-floating,
and attached-floating plant species). "Swamps, marshes, bogs and similar
areas" were mentioned in the Corps-EPA wetland regulatory definition {33
CFR Section 328.3 and 40 CFR Section 230.3) as examples of areas commonly
considered wetlands and to distinguish them from other waters of the
United States, such as aquatic habitats, and uplands. The hydrophytes
that usually dominate wetlands as defined in this document are emergent
plant species (erect, rooted non-woody species such as the common cattail,
Typha latifolia) or woody species, such as the bald cypress (Taxodium
distichum). Submerged species such as water milfoil (Myriophyllum spicatum),
unattached-floating species such as duckweed (Lemna minor), and attached-
floating species such as water lily (Nymphaea odorata) are generally more
characteristic of permanent water areas such as ponds. Although emergent
species may be permanently or temporarily flooded at their bases, they
do not tolerate prolonged inundation of the entire plants (or if tolerant,
do not flower when submerged). Wetland hydrophytes are usually also
vascular plants (a major exception in some areas being bryophytes).
Thus, most wetlands are dominated by emergent vascular plant species,
which may or may not occur in association with vascular or non-vascular
submergent, unattached-floating, and/or attached-floating plant species.
When these non-emergent macroscopic hydrophytes do occur interspersed
with emergent plants in a vegetation unit, the unit should be considered
wetlands if BOX or more of the total percent areal cover is comprised of
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emergent species, assuming it also has hydric soils and wetland hydrology.
Small areas of bare ground or open water may occur interspersed with wetland
vegetation. Under such circumstances, the bare ground (unless it is an
upland inclusion) and open water should be considered part of the wetland
system.
In deciding whether a site is a wetland versus an aquatic hafiitat,
normal seasonal, annual and, where appropriate, long-term cyclic environ-
mental conditions should also be considered. For example, a shallow water
area (e.g., a swale) dominated by annual plants after a natural summer
drawdown would be open water during the wettest part of the year. Such
shallow water areas should be considered wetlands. Likewise, if it can
be documented that long-term cyclic succession from emergents to open
water and back to emergents again is normal for the site involved (e.g.,
a prairie pothole), the site should be considered wetlands.
2. Prevalent Vegetation
The Corps-EPA regulatory definition of wetlands includes the phrase
"a prevalence of vegetation." As used in this manual, the term prevalence
is considered equivalent to dominance. Thus, the prevalent vegetation is
the dominant vegetation. In an ecological sense, a dominant plant species
is one that by virtue of its size, number, production, or other activities,
exerts a controlling influence on its environment and therefore determines
to a large extent what other kinds of organisms are present in the ecosystem
(Odum, 1971). In this document, however, dominance strictly refers to the
spatial extent of a species because the extent is directly discernible or
measurable in the field. Spatially dominant plant species are character-
istically the most common species (i.e., those having numerous individuals
or a large biomass in comparison to uncommon or rare species). In this
sense, a dominant species is either the predominant species (the only
species dominating a unit) or a codominant species (when two or more
species dominate a unit). In the jurisdictional approaches presented
in this Manual, percent areal cover is the standard measure of spatial
extent, except for trees in which case basal area is used. Note: Because
this Manual relies heavily on vegetation, in its absence (e.g., during
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the non-growing season, particularly when dealing with annual species,
or after clearing or filling) historical data (e.g., aerial photographs)
will have to be utilized. Section V in Volume II addresses this situation.
3. Typically Adapted Plants
The words "typically adapted" are also present in the Corps-EPA wetland
definition. Something that is typical is normal, usual or common in occur-
rence (Environmental Laboratory, 1987). An adaptation is a condition of
showing fitness for a particular environment, as applied to characteristics
of a structure, function, or entire organism (Mayr, 1970). These character-
istics make the organism more fit (adapted) for reproduction and/or existence
under conditions of its environment. For example, plant species that gain
a competitive advantage in saturated soil conditions are typically adapted
for such conditions. Various morphological, physiological, and reproductive
adaptations for inundation and/or saturated soil conditions are given in A4b
(page 9).
4. Indicators of Hydrophytic Vegetation
There are a number of indicators of the presence of hydrophytic
vegetation. Some indicators are diagnostic under natural conditions
(i.e., obligate wetland species and plants with morphological, physio-
logical, and/or reproductive adaptations for soil saturation and/or
inundation); others (i.e., facultative species) are indicative of
hydrophytic vegetation 1n the presence of hydrlc soils and hydro-
logic indicators. These indicators of hydrophytic vegetation are
elaborated below.
a. Obligate wetland species. The U.S. Fish and Wildlife Service
(1988) has prepared a national list, a series of regional lists
and a series of state lists of plants that occur in wetlands.
Some of the species on these lists are obligate wetland species
which, under natural conditions, always occur in wetlands. The
presence of dominant obligate wetland species in a vegetation
unit should be considered diagnostic of wetlands as long as the
unit has not been significantly modified hydrologlcally. Dominant
facultative species and non-dominant species may be present as well,
but dominant obligate upland species can not be present.
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The U.S. Fish and Wildlife Service's plant lists were developed
in cooperation with a national panel and regional panels comprised
of personnel from the U.S. Fish and Wildlife Service, Environmental
Protection Agency, Corps of Engineers, and Soil Conservation
Service. There are five things that should be kept in mind when
utilizing the lists.
(1) Because the plant lists were developed for use with the
Classification of Wetlands and Deepwater Habitats of the
United States (Cowardin, et al, 1979), they include
plant species that occur in a number of habitat types
that are not considered wetlands under the Corps-EPA
regulatory program. However, most of these areas are at
least potentially other waters of the United States
(e.g., shallow open water, mudflats, and submerged
aquatic beds), which are frequently dominated by macro-
scopic, non-emergent species (e.g., the various submerged,
unattached-floating, and rooted-floating plants) and/or
microscopic algae.
(2) These lists are consistent with one another in terms of
Indicator status within a given region (e.g., the indicator
status of a given species on the New Jersey state list is
the same as it is on the Northeast regional list, since
New Jersey occurs in the Northeast region). Which list
to use is merely a matter of personal preference.
(3) Because these lists are periodically updated, check with the
U.S. Fish and Wildlife Service or someone on the national or
regional panels to be sure you are using the most recent
versions.
(4) Because the plant lists include only vascular plants,
alternate taxonomic or ecological reference sources will
have to be utilized for determining the indicator status
of non-vascular plants (e.g., bryophytes). This will
be particularly applicable to bogs and swamps in the
Northeast, Pacific Northwest, Alaska, and Hawaii.
(5) It has been suggested by some users of the plant lists
that they are too awkward (i.e., they contain too many
species, too many uncommon species, too many unfamiliar
species). This apparently reflects a misunderstanding
of how the lists will likely be used in a jurisdictional
sense. The fact that a field investigator may not know
all the species on a regional or state list is irrelevant,
since not all the species on a list will occur in a generic
wetland type (e.g., bogs) let alone at a given site.
Thus, at any one time, the field investigator will be
dealing with a small subset of the plants on the list --
a subset determined by the investigator at the site,
not the list. The field investigator will then check the
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dominants found against their indicator status on the list
and make the jurisdictional decision. If field investigators
find that their level of unfamiliarity with the plants at
a given site precludes a scientifically sound and defensible
determination, additional botanical expertise should be
sought. Furthermore, because there are many wetland types
in each region and a determination of all of the dominants
for each type has not been made, potential dominants should
not be eliminated by rule (i.e., a complete list of species
that occur in wetlands will allow for all possibilities).
b. Plants with adaptations for soil saturation and/or inundation.
(1) Plants with morphological adaptations. Plants manifest a
number of morphological adaptations to inundation and/or
saturated soil conditions such as pneumatophores, buttressed
tree trunks, adventitious roots, shallow root systems,
floating stems, floating leaves, polymorphic leaves, multiple
trunks, hypertrophied lenticels, and inflated leaves, stems
or roots. Note: Although a given wetland plant species may
have one or more morphological adaptations, in other wetland
species these adaptations may not be as evident or may even be
non-existent.
(2) Plants with physiological adaptations. Although they are
not as useful because they cannot be observed in the field,
known physiological adaptations, such as the accumulation
of malate in the swamp tupelo (Nyssa sylvatica var. biflora)
and increased levels of nitrate reductase in the eastern
larch (Larix laricina), are associated with inundation and/or
soil saturation.
(3) Plants with reproductive adaptations. Many wetland plants
have reproductive strategies that allow then to exist and
reproduce under inundated or saturated soil conditions.
Some can germinate under low oxygen concentrations; other
have flood-tolerant seedlings. Many species also manifest
prolonged seed viability while inundated, remaining dormant
until soil moisture conditions during natural drawdown are
right for germination.
c. Facultative species. Any combination of the three categories of
facultative species (i.e., facultative wetland, straight facultative,
and/or facultative upland) should be considered indicative of
hydrophytic vegetation if the vegetation unit in which they occur
has hydric soils and one or more hydrologic indicators are at
least periodically present during a significant part of the growing
season (i.e., soil saturation for usually a week or more, ponding
for a long or very long duration, and frequent flooding for long or
very long duration). In addition, obligate upland species must
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either be absent or present only on microsites and/or larger
similar inclusions. In other words, facultative species per se,
even as dominants, are not in and of themselves diagnostic of
wetlands or uplands (i.e., by definition, they should be considered
inconclusive and therefore not necessarily hydrophytic or non-hydro-
phytic). However, an examination of the soils and hydrology at a
site should give an indication as to whether the individual facul-
tative plants at that site are, in fact, occurring under conditions
that would require them to be adapted for life in saturated soils.
If these individuals are growing under saturated soil conditions
for a significant part of the growing season, then they constitute
hydrophytic vegetation.
B. Hydric Soils
1. Definition
A hydric soil is a soil that is saturated, flooded, or ponded long
enough during the growing season to develop anaerobic conditions in the
upper part (Soil Conservation Service, 1987). Such soils usually support
hydrophytic plants.
2. Criteria for Hydric Soils*
Consistent with the above definition, the Soil Conservation Service
(1987) in cooperation with the National Technical Committee for Hydric
Soils developed the following hydric soil criteria.
a. All Histosols except Folists, or
b. Soils in Aquic suborders, Aquic subgroups, Albolls suborder,
Salorthids great group, or Pell great groups of Vertisols that
are:**
(1) Somewhat poorly drained and have water table less than
15 centimeters (0.5 foot) from the surface for a
significant period (i.e., usually a week or more)
during the growing season, or
* These criteria are selected soil properties that are documented in Soil
Taxonomy (Soil Survey Staff, 1975) and the Soil Conservation Service's
Soil Interpretation Records (S0I-5). They are consistent with, but not
always identical to, field soil characteristics of hydric soils (see
Section 4b).
** For an elaboration of these terms, see Soil Taxonomy (Soil Survey Staff,
1975) or Keys to Soil Taxonomy (Department of Agriculture, 1985).
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(2) poorly drained or very poorly drained and have either:
(a) water table at less than 30 centimeters (1.0
foot) from the surface for a significant period
(i.e., usually a week or more) during the growing
season if permeability is equal to or greater
than 15 centimeters/hour (6.0 inches/hour) in
all layers within 50 centimeters (20 inches), or
(b) water table at less than 45 centimeters (1.5 feet)
from the surface for a significant period (i.e.,
usually a week or more) during the growing season if
permeability is less than 15 centimeters/hour (6.0
inches/hour) in any layer within 50 centimeters (20
inches), or
c. Soils that are ponded for long duration or very long duration
during the growing season, or
d. Soils that are frequently flooded for long duration or very long
duration during the growing season.
3. Classification of Hydric Soils
Under the current soil classification system published in Soil Taxonomy
(Soil Survey Staff, 1975), there are two broad categories of hydric soils:
Organic soils (Histosols) and mineral soils. All organic soils are hydric
except for the Folists, which occur mostly in very humid climates from the
Tropics to high latitudes. In the United States, Folists are found mainly
in Hawaii and Alaska (Soil Survey Staff, 1975). Folists are more or less
freely drained Histosols that consist primarily of plant litter that has
accumulated over bedrock. Those Histosols that are hydric are commonly
known as peats and mucks. Mineral soils, on the other hand, consist pre-
dominantly of mineral matter, and contain less than 20% organic matter
by weight (Buckman and Brady, 1969). Mineral soils that are hydric are
saturated long enough to significantly affect various physical and chemical
soil properties. They are usually either gray, mottled immediately below
the surface horizon, or have thick, dark-colored surface layers overlying
gray or mottled subsurface horizons (Environmental Laboratory, 1987).
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4. Indicators of Hydric Soils
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Indicators of hydric soils can be placed into two categories: Soil
series and phases on the national and state hydric soils lists and field
indicators of hydric soils. These indicators are elaborated below.
a. Soil series and phases considered hydric. The Soil Conservation
Service (1987) has developed national and state lists of hydric
soils in conjunction with the National Technical Committee for
Hydric Soils. There are four things that should be kept in mind
when using these lists.
(1) Because these lists are periodically updated, check with the
U.S. Soil Conservation Service or someone on the National
Technical Committee for Hydric Soils to be sure you are using
the most recent versions.
(2) It is always best to verify that the soil at a givert site has
been correctly designated in the county soil survey as to series,
phase or other mapping unit. This can be done by comparing soil
profiles in the field with those described for the site in the
county soil survey. In addition, even if the soil at a given site
has been correctly designated overall, a given mapping unit could
have smaller inclusions of other mapping units within its boundaries
(i.e., a non-hydric soil can have hydric inclusions and vice versa).
In New Jersey, for example, Hammonton mapping units, which are
non-hydric overall and therefore not on the national or state
lists of hydric soils, can have hydric inclusions, such as Atsion
and Pocomoke soils.
(3) Some mapping units (e.g., alluvial land, swamp, tidal marsh, muck,
and peat) may be hydric but will not be on the lists of hydric soils
because they do not yet have series names for the area in question.
Others may not be on the lists because they are recently established
series or phases; others because they are variants or taxadjuncts.
(4) A hydric soil may not appear to be on the hydric soils list
because it is referenced and mapped in an early county soil
survey under another name, (i.e., there could be a synonomy
problem).
Because of the latter three posibilities and perhaps others,
the field soil characteristics at a given site should be given
precedence over how a site 1s mapped on a county soil survey.
However, any divergence from the soil survey or the national or
state lists should be well-documented technically, and unless
there is a good reason to believe otherwise for a given series/
phase (e.g., the exceptions mentioned above), any series/phase
not on the hydric soils lists should be considered non-hydric.
Again though, remember that an otherwise non-hydric soil mapping
unit can have hydric inclusions and vice versa. Note: If problems
develop over interpreting the soils or the county soil survey,
consult a professional soil scientist.
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b. Field evidence of hydric soils.
(1) Organic soils (Histosols). Histosols are organic soils
(mostly peats and mucks) that have organic materials in more
than half (by volume) the upper 80 centimeters (32 inches),
unless the depth to rock or to fragmental materials in less
than 80 centimeters, or the bulk density is very low (Soil
Survey Staff, 1975). A more detailed definition can be found
in Soil Taxonomy (Soil Survey Staff, 1975). Except for Folists,
all organic soils are hydric.
(2) Histic epipedons. A histic epipedon is a 20-40 centimeter
(8-16 inch) soil layer at or near the surface that is saturated
for 30 consecutive days or more during the growing season in
most years and contains a minimum of 20% organic matter when no
clay is present or a minimum of 30% organic matter when 60% or
greater clay is present (Environmental Laboratory, 1987). In
general, a histic epipedon is a thin horizon of peat or muck
if the sod has not been plowed (Soil Survey Staff, 1975).
(3) Mineral soils with mottling and/or gleying. Soil colors can
be very useful indicators of hydric mineral soils. Because
of the anaerobic conditions associated with prolonged water-
logging, soils generally become chemically reduced and gleyed.
With chemical reduction, elements such as iron and manganese
change from the oxidized (ferric and manganic) state to the
reduced (ferrous and manganous) state. Such changes are
manifested in bluish, greenish or grayish colors character-
istic of gleying. Gleyed soil conditions can be determined by
comparing a soil sample with the gley chart in Munsell Soil
Color Charts (Kollmorgen Corporation, 1975). Gleying can
occur in both mottled and unmottled soils.
Mineral soils that are periodically saturated for long
periods during the growing season also are usually hydric.
Under such alternating saturated and unsaturated conditions,
mottles commonly develop. Mottles are spots or blotches of
different color or shades of color interspersed with the
dominant color (Buckman and Brady, 1969). The dominant color
is called the soil matrix. Although the soil matrix is usually
greater than 50% of a given soil layer, the term soil matrix
can refer to a soil layer that has no mottles at all. When
the soil matrix in a mottled soil is gleyed, it is considered
a hydric soil. When the matrix is not gleyed, it is still
considered hydric if it has a chroma of < 2. Likewise, an
unmottled gleyed soil is considered hydric, as are unmottled
soils that are not gleyed, but have a chroma of _< 1. Thus,
gleyed soils, mottled soils with a matrix chroma of £ 2, and
unmottled soils with a matrix chroma £ 1 are all hydric soils.
Soil chroma should be determined using the Munsell Soil Color
Charts (Kollmorgen Corporation, 1975). Note: Because soTI
color is generally not a good indicator in sandy soils (e.g.,
barrier islands), other indicators of hydric soils may have to
be used.
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(4) Aquic or peraquic moisture regime. The aquic moisture regime
is a reducing regime that is virtually free of dissolved
oxygen because the soil is saturated by ground water or by
water of the capillary fringe (Soil Survey Staff, 1975). The
soil is considered saturated if water stands in an unlined
borehole at shallow enough depths that the capillary fringe
reaches the soil surface except in non-capillary pores.
Because dissolved oxygen is removed from ground water by
microorganism, root, and soil fauna! respiration, it is
implicit in the concept of aquic moisture regime that the
soil temperature is above biologic zero (5 degrees centigrade)
at some time while the soil or soil horizon 1s saturated
(Soil Survey Staff, 1975).
Theye are also soils (e.g., saltmarsh soils) in which the
ground water is always at or very close to the surface. The
moisture regimes for these soils is termed peraquic (Soil
Survey Staff, 1975). Although soils with peraquic moisture
regimes would always be hydrlc under natural conditions, those
with aquic moisture regimes would usually be hydric (i.e., they
are hydrlc if they meet the hydrlc soil criteria specified in B2,
page 10).
(5) Sulfidic materials. Sulfidic materials accumulate in soils
that are permanently saturated, generally with brackish
water. Under saturated conditions, the sulfates in water
are biologically reduced to sulfides as the soil materials
accumulate (Soil Survey Staff, 1975). The presence of
sulfidic materials is generally evidenced by the smell of
hydrogen sulfide, which has a rotten egg odor.
(6) Iron and manganese concretions. Concretions are local con-
centrations of chemical compounds (e.g., iron oxide) in
the form of a grain or nodule of varying size, shape,
hardness, and color (Buckman and Brady, 1969). Iron and
manganese concretions are usually black or dark brown and
occur as small aggregates near the soil surface. Iron and
manganese concretions greater than 2 millimeters (0.08
inches) in diameter that occur within 7.5 centimeters (3.0
inches) of the soil surface are evidence that the soil is
saturated for long periods near the surface (Environmental
Laboratory, 1987).
(7) Oxidized root-rhizomes channels associated with living roots
and rhizomes. Some hydrophytes are able to survive under
saturated soil conditions because they have anatomical
adaptations for transporting oxygen to the root zone. In
anaerobic soil, this is manifested by oxidized root-rhizome
channels.
(8) Anaerobic soil conditions. Wetlands manifest at least
periodic soil saturation (waterlogging). When saturation
is long enough, an anaerobic environment develops, which
can result in a highly reduced soil. Under these conditions,
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ferric iron, the oxidized form of iron, is converted to the
reduced form, ferrous iron. The presence of reduced iron 1n
the soil can be detected by the use of a colorlmetric field
test kit. However, this test cannot be used 1n mineral hydric
soils having low iron content, organic soils, and soils that
have been desaturated for significant periods of the growing
season (Environmental Laboratory, 1987).
(9) Other organic materials. In sandy soils (e.g., on barrier
islands), organic materials in the soil profile under the
conditions described below are considered evidence of hydflc
soils (Environmental Laboratory, 1987).
(a) High organic matter in the surface horizon. Because
prolonged inundation and soil saturation result in
anaerobic conditions, organic matter tends to accumulate
above or in the surface horizon of sandy soils. The
mineral surface layer generally appears darker than
the mineral material immediately below it due to
organic matter interspersed among or adhering to
sand particles. Note; Because organic matter also
accumulates on upland soils, in some instances it may
be difficult to distinguish a surface organic layer
associated with a wetland site from litter and duff
associated with an upland site unless the species
composition of the organic materials is determined.
(b) Dark vertical streaking in subsurface horizons. This 1s
the result of the downward movement of organic materials
from the soil surface. When the soil from a vertical
streak is rubbed between the fingers, a dark stain will
result. This may sometimes be associated with a thin
layer of hardened organic matter called an organic pan
or spodic horizon. This pan 1s the result of organic
matter that has moved downward through sandy soils and
has accumulated and become slightly cemented with
aluminum at a point 1n the soil profile representing
the most commonly occurring depth to the water table.
C. Wetland Hydrology
1. Characteristics of Wetland Hydrology
Wetland hydrology 1s the sum total of wetness characteristics in
areas that are inundated or have saturated soils for a sufficient duration
to support hydrophytic vegetation (Environmental Laboratory, 1987). This
inundation or saturation can come from many sources, such as direct precipi-
tation, surface runoff, ground water, tidal Influence, and overland flooding.
Thus, 1f there 1s anything that all wetlands have in common, they are at
least periodically wet (Cowardin, et al, 1979).
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2. Hydrologic Indicators
Although the hydrology parameter may at times be quite evident and
dramatic in the field (e.g., overbank flooding), more often than not this
parameter and its various indicators are usually very difficult to observe.
Furthermore, as opposed to the vegetation and soil parameters, which are
relatively stable, the hydrology parameter exhibits substantial spatial and
temporal variation, making it generally impracticable for delineating
wetland boundaries. Rather, hydrologic indicators are most useful in
confirming that a site with hydrophytic vegetation and hydric soils still
exhibits hydrologic conditions typically associated with such vegetation
and soils (i.e., that the vegetation unit has not been significantly
hydrologically modified to the extent that it supports only remnant,
generally stressed and/or dying, hydrophytic vegetation and drained hydric
soils). In other words, whereas hydrologic indicators can sometimes be
diagnostic of the presence of wetlands, they are generally either opera-
tionally impracticable (in the case of recorded data) or technically
inaccurate (in the case of field indicators) for delineating wetland
boundaries. In the former case, surveying the wetland boundary is generally
too time consuming (even if a given elevation corresponds with the "wetland
hydrologic boundary," which is unlikely); in the latter case, it should be
obvious that indicators of flooding frequently extend well beyond the
wetland boundary. Consequently, in the jurisdictional approaches presented
in this Manual, hydrophytic plants and hydric soils are used to spatially
bound wetlands.
Hydrologic indicators associated with wetlands fall under two categories:
Recorded data and field data. These indicators are elaborated below.
a. Recorded data. Recorded data can be obtained from tide gauges,
stream gauges, flood predictions, historical data (e.g., aerial
photographs and soil surveys), piezometers, etc. The U.S. Geo-
logical Survey, the Soil Conservation Service and the Corps of
Engineers are three good sources of recorded hydrologic data.
b. Field data.
(1) Visual observation of inundation. An obvious hydrologic
indicator is inundation (flooding or ponding). Although
visual evidence of inundation is most commonly obtained
for wetlands along estuaries, rivers, streams, and lakes,
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inundation can sometimes be observed in wetlands occurring
at other geomorphological settings as well, including isolated
depressional wetlands. Note: It is not necessary to directly
demonstrate inundation. It 1s only necessary to show through
recorded data that the soil surface is at least periodically
inundated during a significant part of the growing season.
Ponding for long or very long duration and frequent flooding
for long or very long duration are considered signficant.
The terms "long duration," "very long duration," and
"frequently flooded" are defined 1n Appendix A.
(2) Visual observation of soil saturation. Evidence of soil
saturation can be obtained from examining a soil pit after
sufficient time has passed to allow water to drain Into the
hole. The amount of time required will depend upon the
texture of the soil. For example, water will drain more
slowly into a soil pit dug in a clayey soil as opposed to a
sandy one. In some heavy clay soils, however, water may not
rapidly move into the hole even when the soil is saturated.
Under these circumstances, it may be necessary to examine
the sides of the soil pit for seepage. Note: The depth to
saturated soil will always be somewhat higher in the soil
profile than the standing water due to the upward movement
of water in the capillary zone.
For soil saturation to have a significant Impact on the
plants in a vegetation unit, it must occur within the major
portion of the root zone (Environmental Laboratory, 1987).
For most species occurring in wetlands, particularly herbaceous
plants, the majority of the roots and rhizomes generally
occur within the upper 30 centimeters (12 inches) of soil*
Note: It is not necessary to directly demonstrate soil
saturation. It is only necessary to show that the soil is
at least periodically saturated during a significant part of
the growing season (i.e., usually a week or more). For
example, a forested wetland with undrained hydric soils and
a seasonally saturated hydrologic regime may not be saturated
within 12 inches of the surface in the the summer or fall.
This is to be expected since it is a reflection of the normal
hydrological variability that occurs with seasonally saturated
systems. It would be inappropriate under these circumstances
to indicate that the hydrological parameter is not met, if
the site really has saturated soils during a significant
part of the growing season. Rather, based upon the presence
of undrained hydric soils and supportive hydrologic information
(e.g., water table conditions given for the series/phase in
the national or state hydric soils lists and/or county soil
surveys), the field investigator should indicate that the
hydrology parameter is met, the rationale being that significant
soil saturation would be expected during the wetter part of
the growing season. Similarly, the presence of saturated soils
at a site during the non-growing season does not necessarily
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mean that the soils will be periodically saturated during a
significant part of the growing season and that the hydrology
parameter is met. Thus, when considering the hydrology parameter
in the field, the time of the year, as well as the significance
of antecedent weather conditions (e.g., recent storm events)
and long-term droughts should be taken into consideration.
Note: If drainage has occurred at a site because of ditching
and/or regional ground water withdraw by wells, the significance
of these hydrologic changes will have to be determined. In most
instances, however, the successional responses of the vegetation
at a known wetland site that has been hydro!ogically modified
(e.g., ditched) will be more useful than a documented hydrologic
change, such as an arbitrarily established drop in water table,
in determining whether the site is still a wetland. This situation
is further addressed in Section V of Volume II.
(3) Sediment deposits. Tidal flooding 1n estuaries and flooding
along non-tidal rivers, streams, and lakes frequently results
in the deposition of Inorganic or organic sediments on live
vegetation, debris, and stationary man-made structures. This
is frequently manifested as a fine layer of silt. S1lt is also
sometimes evident at the soil surface on small debris.
(4) Water marks. Water marks are frequently found on tree trunks
and fixed man-made structures.
(5) Drift lines. Like watermarks and sediment deposits, drift lines
are commonly found along rivers, streams and lakes. Debris (e.g.,
plant parts, sediment, and assorted litter) 1s frequently left
stranded in plants, on man-made structures, and at other obstruc-
tions as the flood-waters recede.
(6) Surface scouring. Surface scouring occurs along floodplalns where
overbank flooding erodes sediments (e.g., at the bases of trees).
The absence of leaf litter from the soil surface 1s also sometimes
an indication of surface scouring.
(7) Water-stained leaves. Forested wetlands that contained standing
water earlier 1n the year will frequently have water-stained
leaves lodged on the forest floor. These leaves are generally
grayish or blackish 1n appearance.
(8) Bare areas. Forested wetlands that contain standing waters for
relatively long duration will sometimes have areas of bare or
essentially bare soil. This Is sometimes associated with local
depressions.
(9) Moss lines. Because of standing water of long or very long
duration, upland mosses will tend to occur on tree trunks and
shrub stems no lower 1n elevation than the height of the standing
water. This results 1n a moss line above which the site 1s not
significantly Inundated. This "stranded" moss line can be quite
obvious during the dry part of the year.
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(10) Wetland drainage patterns. Many wetlands (e.g., tidal marshes
and floodplain wetlands) have characteristic meandering or braided
drainage patterns that are readily recognized in the field or on
aerial photographs and occasionally on togographic maps.
(11) Morphological plant adaptations. Many plants have developed
morphological adaptations in response to inundation and/or soil
saturation (see A4b, page 9). As long as there is no evidence
of significant hydrological modifications, these adaptations
can be used as hydrologic indicators.
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SECTION IV: OVERVIEW OF JURISDICTIONAL APPROACHES
A. General
Prior to making a jurisdictional determination, "1t is.generally necessary
to gather preliminary data and scope out the delineation effort. This will
allow the field investigator to decide which of the three approaches presented
1n Volume II 1s applicable to the project or site 1n question. The simple
jurisdictional approach 1s for routine situations wherein a field investigator
needs only to traverse the majority of the site and record data, for the most
part, from ocular Inspection. The detailed jurisdictional approach is generally
for large and/or controversial sites or projects; it entails establishing
transects and sample plots. Both approaches should give the same results
since the upland-wetland boundary is determined in a similar fashion. The
detailed approach, however, allows for more extensive documentation. In
addition to traversing the majority of the site (simple approach) and estab-
lishing transects and sample plots (detailed approach), both of these juris-
dictional approaches involve a number of specific steps. Five of these steps,
which are basic to both approaches, are elaborated in IVB below. The entire
sequence of steps for the simple and detailed approaches, including the
sampling protocols, 1s presented 1n Volume II. The third jurisdictional
approach should be used for atypical situations (I.e., situations where one
or more indicators of vegetation, soil and/or hydrology cannot be found due
to the effects of recent human activities or natural events) or when normal
seasonal, annual or long-term cyclic variations 1n environmental conditions
result from causes other than human activities or catastrophic natural events.
This approach, depending upon the circumstances, is used In conjunction with
either the simple or detailed approaches; 1t too 1s presented 1n Volume II.
There are a number of ways to effectively sample vegetation. Many
procedures will produce essentially the same results and some procedures
may be appropriate for certain vegetation types but not for others. The
vegetation sampling procedure presented in Volume II 1s effective in the
field, but may have to be adjusted in some instances because of site con-
ditions and the nature of the vegetation. Other information on vegetation
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sampling is included in books by Barbour, Burk and Pitts (1987), Cain and
Castro (1959), Curtis (1971), Daubenmire (1968), Greig-Smith (1983), Kuchler
(1967), Mueller-Dombois and Ellenberg (1974), Oosting (1956), and Smith
(1974). Note: In sampling vegetation, field investigators should keep in
mind that they are not doing detailed phytosociological studies. They only
need enough information to be able to judge the dominant plant species and,
in conjunction with soils and hydrology as appropriate, establish the extent
of jurisdiction.
B. Basic Steps for the Simple and Detailed Jurisdictional Approaches
1. Horizontal stratification of the site into vegetation units.
Vegetation units (i.e., patches, groupings, or zones of plants that
are evident in overall plant cover and which appear distinct from other
such units) should be distinguished in the field based upon an examination
of vegetation structure and floristic composition. Vegetation units can
also be determined through analysis of "vegetation signatures" on aerial
photographs as long as a representative number of units are verified by
field checking. Once this step is complete, field investigators should
have, either in their minds or on a vegetation map, topographic map, or
annotated aerial photograph, a good indication of the various vegetation
units at the site.
2. Determination of the dominant plant species.
This Manual relies heavily on the presence of dominant plant species.
The spatially dominant species in a vegetation unit are characteristically
the most common species (i.e., those having numerous individuals or a large
biomass in comparison to uncommon or rare species). Percent areal cover is
the standard measure of spatial extent and dominance used in this Manual,
except for trees in which basal area is assessed. Percent areal cover is
an estimate of the area covered by the foliage of a plant species projected
onto the ground. Because of species overlap, each species should be treated
separately in sampling, and the total areal cover of all species will
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frequently exceed 100?. Basal area is a measure of dominance in forests
expressed as the area of a trunk of a tree at diameter breast height or as
the total of such areas for all trees in a given space (Curtis, 1971).
Whether a species is dominant or not in a vegetation unit will depend
upon the nature of the vegetation. In a monotypic vegetation type, the
species present is clearly predominant and thus the dominant species 1n
this instance. More frequently, however, two or more species will codominate
a vegetation unit in which case all of the codominants should be considered
dominant species. It 1s not uncommon to have a number of species dominating
a vegetation unit, especially at forested sites where a few species may
dominate each vertical stratum. Thus, the percent areal cover or the basal
area necessary for a species to be a dominant should be flexible because
of the naturally occurring spatial heterogeneity of some vegetation.
The approach taken in this Manual for determining the dominant species
1n a vegetation unit is an inductive one in which the dominant plants are
determined after the data are collected, as opposed to collecting data
on only what are considered the dominant plants based upon some a priori
threshold. Although vegetation sampling protocols for the simple and
detailed approaches vary somewhat, the basic procedure for determining
the dominant plants 1n a vertical stratum can best be explained using the
understory stratum of a forested site as an example. Under the detailed
approach, this first entails quantifying the average percent areal cover
of each understory species. Next, the understory species are ranked
according to their average percent areal cover; then the average percent
areal cover values for all the understory species are summed. Lastly, the
average percent areal cover values of the ranked understory species are
cumulatively summed until 50% of the total average percent areal cover
values for all understory species 1s reached or Initially exceeded. All
of the understory species contributing to this 50% threshold are considered
dominants. An essentially similar procedure Is applied to any shrubs,
woody vines, saplings and trees at the forested site. Thus, one or more
species always dominates each stratum in a vegetation unit. A more detailed
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explanation of this procedure is given isn Volume II. Note: The 50$ rule
used in this Manual is for determining the dominant species in either an
entire vegetation unit (simple approach) or a sample plot (detailed
approach). It should not be confused with the Corps of Engineers
(Environmental Laboratory, 1987) 50% rule for determining hydrophytic
vegetation. Under that rule, greater than 50% of the dominant plant
species in a vegetation unit must be obligate wetland species,
facultative wetland species, and/or straight facultative species for
hydrophytic vegetation to be present.
3. Determination of the indicator status of the dominant species in the
vegetation unit using the U.S. Fish and Wildlife Service's national,
regional or state lists of plants that occur in wetlands.
Species on the lists are classified either as obligate wetland species
or one of the three categories of facultative species (facultative wetland,
facultative, and facultative upland). Note: To avoid confusion, the term
"straight facultative" is used in lieu of "facultative" in this Manual.
Unless there is a good technical reason to believe otherwise for a given
species, any vascular plant species not on these lists should be considered
an obligate upland species. However, plant species that are on the lists,
but for which a final indicator status has not yet be determined should
not be considered obligate upland species. Furthermore, any divergence
from an indicator status on the lists should be well-documented technically
on a species by species basis. However, because the national, regional and
state lists are based upon the National List of Scientific Plant Names
(Soil Conservation Service, 1982), the scientific names of some species
listed may not be readily recognized by a field investigator (i.e., the
investigator may be more familiar with a more commonly used taxonomlc
synonym). It is particularly important for the field investigator to be
aware of this since a species may appear to be not on the lists and therefore
be considered an obligate upland species by the investigator, whereas it
may really be on the lists under its currently accepted scientific name.
A brief check of the synonyms listed in Volume II of the National List of
Scientific Plant Names should prevent this problem.
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4. Decision on which vegetation units at the site are wetland units.
Once the vegetation units have been established and the dominant plant
species and their indicator status have been determined, decisions can be
readily made on which units are wetlands versus uplands. This should be
done by examining the data summary sheets in conjunction with a thorough
understanding of the rationale presented in Section II of Volume I. Two
optional tools (a Jurisdictional Decision Flow Chart and a Jurisdictional
Decision Diagnostic Key) presented in Volume II will expedite and conceptually
guide these jurisdictional decisions. Two approaches were developed to allow
user flexibility, since some field investigators may feel more comfortable
using one rather than the other; however, they closely track each other and
will lead to the same jurisdictional decisions. For example, the flow
chart and key both indicate that the presence of dominant obligate plant
species, whether obligate wetland or obligate upland, is generally diagnostic
1n Itself. Specifically, If one or more dominant plant species in a vegeta-
tion unit is an obligate wetland species, the vegetation unit (and the site
1f it 1s a monotypic site) is a wetland and there is no need to consider
soils and hydrology, other than to verify that there have been no significant
hydrologlc modifications. Likewise, the presence of one or more dominant
obligate upland plant species is conclusive evidence of the presence of
uplands. On the other hand, by definition, the presence of one or more
dominant facultative species in a vegetation unit, even the presence of
all facultative wetland dominants, is not truly diagnostic despite the
fact the latter situation in particular would strongly suggest that the
unit is a wetland. Therefore, if only facultative species dominate a
vegetation unit, the flow chart and key direct Investigators to the soil
and hydrologic parameters to help determine whether the vegetation unit 1s
wetland. Note: Although these tools will be particularly helpful to
people who are not that familar with the Field Methodology, their use is
optional and jurisdictional determinations can be conducted without them.
In some instances, a mix of dominant obligate wetland species and
dominant obligate upland species will occur in the same vegetation unit.
These exceptions are reflected in the flow chart and key. They are either
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a consequence of (1) relatively dry mlcrosites and/or larger similar
inclusions (which support the upland species), (2) relative wet microsites
and/or larger similar inclusions (which support the wetland species), or
(3) plant succession resulting from natural or man-induced disturbances
(e.g., the landward edge of a tidal marsh that 1s encroaching on an
adjacent upland forest due to sea level rise and a site that has been
drained but at which wetland plant species still persist but upland
species are invading, respectively). When a mix of dominant obligate
wetland species and dominant obligate upland species occurs, it 1s
necessary to check to see if the site has been appropriately hori-
zontally stratified and to adjust accordingly. If the obligate upland
plants occur on dry mlcrosites or similar larger Inclusions, 1t 1s
necessary to either show these local areas as Individual upland units
or consider the site to be wetlands but acknowledge the presence of
local upland areas in a written description of the site. A comparable
procedure should be used for local wet areas 1n an otherwise upland
site. As long as there are definable vegetation units, however, they
should be handled individually. The minimum size treatable (i.e., the
minimal mapping unit) will depend upon site conditions (e.g., size and
access), plant physiognomy, and the tools available (e.g., type and
quality of aerial photographs). Nevertheless, every attempt should
be made to separately treat small units (i.e., to finely horizontally
stratify) in order to segregate any discrete upland units in a wetland
matrix (or vice versa) that could otherwise bias a jurisdictional
determination.
If there 1s a rather uniform intermixed distribution of dominant
obligate wetland species and dominant obligate upland species (the
various subcategories of facultative species may be present too), then
the unit is probably a naturally or unnaturally disturbed one where
successlonal changes are occurring. Under these circumstances, either
a 50% rule will have to be applied to the obligate species, or as an
alternative plant vigor and reproduction (e.g., seedlings and saplings 1n
a forested site) may give a good Indication of the direction of vegetation
change at the unit or site. For example, a comparison of the vegetation
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at a hydrologically disturbed wetland site with the vegetation at an
"undisturbed" wetland site (control) should indicate which direction the
vegetation is going successionally (i.e., the same, wetter or drier) and
therefore Indirectly whether the site Is still wetlands hydrologically.
Note; When natural or man-Induced disturbances occur, the field Investigator
should apply Section V (Approach for Atypical Situations and/or Normally
Variable Environmental Conditions) of Volume II 1n conjunction with the
simple or detailed approach as appropriate.
5. Delineation of the upland-wetland boundary.
Depending upon the jurisdictional approach used, there are a number of
options for indicating the extent of wetlands at a site. Under the simple
approach, the extent of wetlands can be conveyed in either (1) a written
technical report, (2) on aerial photographs/maps or on overlays thereof,
or (3) by a ground delineation. When the technical report option is chosen,
the various vegetation units should be described in detail, including
information on the dominant plant species and soil and hydrologlc conditions
as appropriate. Under this option and the aerial photograph/map option, It
should be indicated that the extent of wetlands at the site will essentially
coincide with the extent of wetland vegetation units. It should also be
indicated that, if necessary, a more definitive boundary can be established
by an on-site ground delineation. If the ground delineation option 1s
chosen, the interface between any upland vegetation units and any wetland
vegetation units 1s examined and the upland-wetland boundary 1s actually
staked or flagged on the ground. The detailed approach requires a ground
delineation, although It can be done in conjunction with a written technical
report and/or aerial photographs/maps if desired. The basic steps for
delineating the upland-wetland boundary on the ground under the simple
and detailed approaches are elaborated in Volume II.
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SECTION V: LITERATURE CITED
American Society of Agricultural Engineers. 1967. Glossary of soil and
and water terms. Special Publication SP-04-67. 45 pp.
Avery, E.T. 1967. Forest measurements. McGraw-Hill Book Company, N.Y.
Barbour, M.G., J.H. Burk and W.D. Pitts. 1987. Terrestrial plant ecology.
The Benjamin/Cummings Publishing Company, Inc., Menlo Park, California.
634 pp.
Buckman, H.O. and N.C. Brady. 1969. The nature and properties of soils.
The Macmillan Company, Ontario, Canada.
Cain, S.A. and G.M. de Oliveira Castro. 1959. Manual of vegetation analysis.
Harper & Row, N.Y. 325 pp.
Cowardin, L.M., V. Carter, F.C. Golet and E.T. LaRoe. 1979. Classification
of wetlands and deepwater habitats of the United States. FWS/OBS-79-31.
103 pp.
Curtis, J.T. 1971. The vegetation of Wisconsin. The Univ. of Wisconsin Press.
657 pp.
Daubenmire, R.F. 1968. Plant communities. Harper & Row, N.Y. 300 pp.
Department of Agriculture. 1985. Keys to soil taxonomy. Soil Management .
Support Services Technical Monograph No. 6. 244 pp.
Dilworth, J.R. and J.F. Bell. 1978. Variable plot sampling—variable plot
and three-p. O.S.U. Book Stores, Inc., Corvallis, Oregon.
Environmental Laboratory, 1987. Corps of Engineers Wetlands Delineation Manual.
Technical Report, Y-87-1. U.S. Army Engineers Waterways Experiment
Station, Vicksburg, Mississippi.
Environmental Protection Agency. 1980. Environmental Protection Agency
rationale for identifying wetlands. 5 pp.
Greig-Smith, P. 1983. Quantitative plant ecology. The Univ. of California
Press.
Kollmorgen Corporation. 1975. Munsell soil color charts. Baltimore, Maryland.
Kuchler, A.W. 1967. Vegetation mapping. The Ronald Press Company, N.Y. 472 pp.
Mayr, E. 1970. Populations, species and evolution. Harvard Univ. Press.
453 pp.
Mueller-Dombois, D. and H. Ellenberg. 1974. Aims and methods of vegetation
ecology. John Wiley & Sons, N.Y. 547 pp.
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Odum, E.P. 1971. Fundamentals of ecology. W.B. Saunders Company,
Philadelphia, Pennsylvania. 574 pp.
Oosting, H.J. 1956. A study of plant communities. W.H. Freeman & Company,
San Francisco. 440 pp.
Sipple, W.S. 1985. Peat analysis for coastal wetland enforcement cases.
Wetlands 5:147-154.
Sipple, W.S. 1988. Report on the results of field testing the Environmental
Protection Agency's interim final Wetland Identification and Delineation
Manual during 1987.
Smith, R.L. 1974. Ecology and field biology. Harper & Row, N.Y. 850 pp.
Soil Conservation Service. 1982. National List of scientific plant names.
Vol. I. List of plant names. Vol. II. Synonomy. SCS-TP-159.
Soil Conservation Service. 1987. Hydric soils of the United States. In
cooperation with the National Technical Committee for Hydric Soils.
Soil Survey Staff. 1975. Soil Taxonomy. Agricultural Handbook No. 436,
Soil Conservation Service, U.S. Department of Agriculture. 754 pp.
Soil Survey Staff. (In preparation). Soil survey manual. Soil Conserva-
tion Service, U.S. Department of Agriculture.
U.S. Fish & Wildlife Service. 1988. National list of plants that occur
in Wetlands. In cooperation with the National Wetland Plant List
Review Panel.
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APPENDIX A
GLOSSARY
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APPENDIX A
GLOSSARY
Adaptation--The condition of showing fitness for a particular environment,
as applied to characteristics of a structure, function, or entire organism
(Mayr, 1970). These characteristics make the organism more fit (adapted)
for reproduction and/or existence under the conditions of its environment.
Plant species that gain a competitive advantage in saturated soil conditions
are typically adapted for such conditions.
Aerobic--A condition in which molecular oxygen is present in the environment.
Anaerobic—A condition in which molecular oxygen is absent from the environment
(Soil Conservation Service, 1987). This commonly occurs in wetlands when
soils are saturated by water.
Aquatic habitats—Habitats, other than wetlands, that generally have shallow
or deep water. The water can be intermittently (e.g., an intertidal flat) or
permanently (e.g., a pond) present. Shallow water areas sometimes support
non-emergent hydrophytes.
Aquic moisture regime—A reducing regime in which the soil is virtually free
of dissolved oxygen because it is saturated by ground water or by water of
the capillary fringe. Some soils (e.g., salt marshes) are so wet that the
ground water is always at or very close to the soil surface and they are
considered to have a peraquic moisture regime (Soil Survey Staff, 1975).
Basal area—A measure of dominance in forests expressed as the area of a
trunk of a tree at diameter breast height (dbh) or as the total of such
areas for all trees in a given space (Curtis, 1971).
Baseline--A line, generally a highway, unimprove road, or some other evident
feature, from which transects extend into a site for which a wetland juris-
dictional determination is to be made.
Bryophytes—A major taxonomic group of non-vascular plants comprised of
1iverworts, horned liverworts, and true mosses.
Capillary zone—The zone of soil essentially saturated with water, in which
pores become filled as a result of surface tension (American Society of
Agricultural Engineers, 1967).
Chemical reduction—Any process by which one compound or ion acts as an
electron donor. In such cases, the valence state of the electron donor is
decreased (Environmental Laboratory, 1987).
Cover class—As used in this Manual, a category into which plant species
would fit based upon their percent areal cover. The cover classes used
(midpoints in parentheses) are T=
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A-2
Diameter breast height (dbh)--The diameter of a tree trunk at 1.37 meters
(4.5 feet) above the ground.
Dominant—In a ecological sense, a dominant plant species is one that by
virtue of its size, number, production, or other activities, exerts a
controlling influence on its environment and therefore determines to a
large extent what other kinds of organisms are present in the ecosystem
(Odum, 1971). In this document, however, dominance strictly refers to the
spatial extent of a species because spatial extent is directly discernible
or measurable in the field. In this sense, a dominant species is either
the predominant species (i.e., the only species dominating a unit) or a
codominant species (i.e., when two or more species dominate a unit). The
measures of spatial extent utilized in this Manual (percent areal cover
and basal area) are defined elsewhere in the glossary.
Duff—The matted, partly decomposed, organic surface layer of forested
soils (Buckman and Brady, 1969). The O2 horizon.
Facultative species—Species that can occur both in wetlands and uplands.
There are three subcategories of facultative species (facultative wetland,
straight facultative, and facultative upland). Under natural conditions,
a facultative wetland species is usually (estimated probability of 67-99$)
found in wetlands, but is occasionally found in uplands; a straight facul-
tative species has basically a similar likelihood (estimated probability
of 34-66%) of occurring in both wetlands and uplands; a facultative upland
species is usually (estimated probability of 67-99%) found in uplands, but
is occasionally found in wetlands.
Fern allies—A group of non-flowering vascular plants comprised of clubmosses
(Lycopodiaceae), small clubmosses (Selaginellaceae), horsetails (Equisetaceae),
and quillworts (Isoetaceae).
Flooded—A condition in which the soil surface is temporarily covered with
f1owing water from any source, such as streams overflowing their banks,
runoff from adjacent or surrounding slopes, inflow from high tides, or any
combination of sources (Soil Conservation Service, 1987).
Flora—A list of plant taxa in a geographic area of any size. This could be
a simple list or a more detailed one that includes taxonomic descriptions,
diagnostic keys, distribution data, etc. Compare this term with the term
"vegetation."
Folist—A more or less freely drained Histosol that consists primarily of
plant litter that has accumulated over bedrock (Soil Survey Staff, 1975).
Forbs—Broadleaf herbaceous plants, in contrast to bryophytes, ferns, fern
allies, and graminoids.
Frequently flooded—A class of flooding in which flooding is likely to occur
often under usual weather conditions (more than 50% chance of flooding in
any year, or more than 50 times in 100 years) (Soil Conservation Service,
1987).
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A-3
Gleying—A soil condition 1n mineral soils resulting from prolonged water-
ToggTng 1n the presence of organic matter. Gleylng occurs under reducing
conditions In saturated soils. With chemical reduction, elements such as
iron and manganese change from the oxidized (ferric and manganic) state
to the chemically reduced (ferrous and manganous) state. Such changes
are manifested in bluish, greenish or grayish colors characteristic of
gleying. Gleyed soil conditions can be determined by comparing a soil
sample with the gley chart in Munsell Soil Color Charts (Kollmorgen
Corporation, 1975). Gleying can occur 1n both mottled and unmottled
soils.
Graminoids—Grasses (Gramineae) and grasslike plants, such as sedges
(Cyperaceae) and rushes (Juncaceae).
Growing season—The portion of the year when soil temperatures are above
biologic zero (5 degrees C), as defined in Soil Taxonomy (Soil Survey Staff,
1975). The following growing season months are assumed by the Soil Conser-
vation Service (1987) for each of the soil temperature regimes:
Isohyperthermlc: January-December
Hyperthermic:
Isothermic:
Thermi c:
Isomesic:
Meslc:
Frigid:
Crylc:
Pergelic:
February-December
January-December
February-October
January-December
March-October
May-September
June-August
July-August
Habitat—An environment occupied by plants and animals,
Herbaceous plants—Plants without persistent woody stems above the ground.
Herbaceous plants are commonly called herbs.
Histic epipedon—An 8-16 Inch (20-40 centimeter) soil layer at or near-the
surface that is saturated for 30 consecutive days or more during the growing
season in most years and contains a minimum of 20% organic matter when no
clay 1s present or a minimum of 30% organic matter when 601 or greater
clay is present (Environmental Laboratory, 1987). In general, a thin
horizon of peat or muck if the soil has not been plowed (Soil Survey Staff,
1975).
Histosol—An order in Soil Taxonomy composed of organic soils (mostly peats
and mucks) that have organic materials 1n well over half the upper 80
centimeters (32 inches) unless the depth to rock or to fragmental materials
1s less than 80 centimeters (a rare condition), or the bulk density is
very low (Soil Survey Staff, 1975).
Horizontal stratif 1 cation—The division of the vegetation at a site into
vegetation units (I.e., various patches, groupings, or zones).
Hydrlc soil—A soil that 1s saturated, flooded, or ponded long enough during
the growing season to develop anaerobic conditions in the upper part (Soil
Conservation Service, 1987).
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A-4
Hydrophytes—Large plants (macrophytes), such as aquatic mosses, liverworts,
non-microscopic algae and vascular plants, that grow in permanent water
or on a substrate that is at least periodically deficient of oxygen as a
result of excessive water content. This term includes both aquatic plants
and wetland plants.
Hydrophytic vegetation— Macrophytic plant life growing in water or on a
substrate that is at least periodically deficient in oxygen as a result of
excessive water content.
Inundated—A condition in which a soil is periodically or permanently flooded
or ponded by water.
Litter—The undercomposed plant and animal material found above the duff
layer of forest floors (Buckman and Brady, 1969). The Oi horizon.
Long duration—A duration class in which inundation for a single event
ranges from 7 days to 1 month (Soil Conservation Service, 1987).
Mineral soil—A soil consisting predominantly of, and having its properties
determined predominantly by, mineral matter. Mineral soils usually contain
less than 20% organic matter by weight (Buckman and Brady, 1969).
Monotypi c vegetati on--Vegetati on that is dominated by only one plant species.
Mottling—Spots or blotches of different color or shades of color interspersed
with the dominant color (Buckman and Brady, 1969). The soil material having
the dominant color is called the soil matrix.
Muck--Highly decomposed organic material in which the original plant parts
are not recognizable (Buckman and Brady, 1969).
Obligate upland species—Species that, under natural conditions, always
occur in uplands (i.e., greater than 99% of the time). The less than 1%
is to allow for anomalous wetland occurrences (i.e., occurrences that are
the result of man-induced disturbances and transplants).
Obligate wetland species—Species that, under natural conditions, always
occur in wetlands (i.e., greater than 99% of time). The less than II is
to allow for anomalous upland occurrences (i.e., occurrences that are the
result of man-induced disturbances and transplants).
Organic pan—A layer (i.e., spodic horizon), usually occurring at 30-75
centimeters (12-30 inches) below the soil surface in coarse-textured soils,
in which organic matter and aluminum (with or without iron) accumulated at
the point where the top of the water table most often occurs (Environmental
Laboratory, 1987).
Peat—The sod layer at and near the surface of a wetland, as well as the
deeper, partially decomposed, vegetation into which the sod eventually
grades (Sipple, 1985).
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A-5
Pedon—The smallest unit of soil that can be classified (Soil Survey Staff,
in preparation).
Polypedon--A group of contiguous pedons of a single soil series (Soil
Survey Staff, in preparation).
Percent area! cover—An estimate of the area covered by the foliage of a
plant species projected onto the ground. It is determined independent of
other species, and because of species overlap, the total areal cover for
all species will frequently exceed 100%, particularly for forested sites.
Periodic—Occurring or recurring at intervals which need not be regular or
predictable. Used here in reference to inundation or saturation of a
wetland soil.
Permeability—The quality of the soil that enables water to move downward
through the profile, measured as the number of inches per hour that water
moves downward through the saturated soil (Soil Conservation Service,
1987).
Physiognomy—A term referring to the overall appearance of the vegetation,
as opposed to its floristic composition. This is the result of the various
life forms (e.g., trees, shrubs, and herbs) and their distribution in each
stratum (Kuchler, 1967).
Ponded—A condition in which water stands in a closed depression. The
water is removed only by percolation, evaporation, or transpiration (Soil
Conservation Service, 1987).
Poorly drained—A condition in which water is removed from the soil so
slowly that the soil is saturated periodically during the growing season
or remains wet for long periods (Soil Conservation Service, 1987).
Prevalence—This term is equivalent to dominance. Thus, the prevalent
vegetation is the dominant vegetation.
Quadrats--Sampling units or plots that may vary in size, shape, number,
and arrangement-, depending upon the nature of the vegetation and the
objectives of the study (Smith, 1974).
Root zone—That part of the soil profile that is or can be occupied by plant
roots and rhizomes. For most plant species occurring in wetlands, particu-
larly herbaceous plants, the majority of the roots and rhizomes generally
occur within the upper 30 centimeters (12 inches) of soil.
Sapling—A young tree between 1 and 10 centimeters (0.4 and 4 inches) in
diameter 1.37 meters (4.5 feet) above the ground surface.
Saturated—A condition in which all voids (pores) between soil particles in
the root zone are filled with water to a level at or near the soil surface
(maximum water retention capacity). Saturation may be periodic or permanent.
Significant saturation during the growing season is considered to be usually
a week or more (Soil Conservaton Service, 1987).
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A-6
Seedling--A young tree that 1s smaller than a sapling and generally less than
1 meter (3.28 feet) high.
Shrub—A woody plant that at maturity is usually less than 6.1 meters (20
feet) tall and generally exhibits several erect, spreading or prostrate
stems and has a bushy appearance (e.g., smooth alder, Alnus serrulata)
(Cowardin, et a^, 1979).
Soil—A dynamic natural body on the surface of the earth in which plants
grow, composed of mineral and organic materials and living forms. Also
the collection of natural bodies occupying parts of the earth's surface
that support plants and that have properties due to the Integrated effect
of climate and living matter acting upon parent material, as conditioned
by relief, over periods of time (Buckman and Brady, 1969).
Soil color—A characteristic of soil that has three variables: chroma,
hue, and value. The hue notation of a color Indicates its relationship to
red, yellow, green, blue, and purple; the value notation indicates its
lightness; and the chroma notation Indicates Its strength or departure
from a neutral of the same lightness (Kollmorgen Corporation, 1975).
Soil horizon—A layer of soil, approximately parallel to the soil surface,
with distinct characteristics produced by soil-forming processes (Buckman
and Brady, 1969). For example, the A horizon 1s the upper-most mineral
horizon. It lies at or near the soil surface and is where maximum soil
leaching occurs.
Soil matrix—The portion (usually greater than 50?) of a given soil layer
that has the dominant color (Environmental Laboratory, 1987).
Soil phase—A subdivision of a soil series based on features such as slope,
surface texture, stoniness, and thickness (Soil Conservation Service,
1987).
Soil profile—A verticle section of the soil through all the horizons and
extending into the parent material (Buckman and Brady, 1969).
Soil series—A group of soils having horizons similar in differentiating
characteristics and arrangements in the soil profile, except for texture
of the surface layer (Soil Conservation Service, 1987).
Somewhat poorly drained—A condition 1n which water is removed slowly enough
that the soil Is wet for significant periods during the growing season
(Soil Conservation Service, 1987).
Species area curve—As used in this Manual, the curve on a graph produced
when plotting the cumulative number of plant species found In a series of
quadrats against the cumulative number or area of those quadrats. It is
used here in the detailed jurisdictional approach to determine the number
of quadrats sufficient to adequately survey the herbaceous understory.
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A-7
Taxadjunct--A polypedon that has properties outside the range of any
recognized soil series (Soil Survey Staff, in preparation).
Topographic contour—An imaginery line of constant elevation along the
ground (Environmental Laboratory, 1987). A contour line is the corres-
ponding line on a topographic map.
Transect—As used in this Manual, a line along which sample plots are
established for collecting vegetation, soil, and hydrology data.
Tree—A woody plant that at maturity is usually 6.1 meters (20 feet) or
more in height and generally has a single trunk, unbranched to about three
feet above the ground, and more or less definite crown (e.g., red maple,
Acer rubrum) (Cowardin, et al_, 1979). As distinguished from a sapling,
a tree is greater than lTTcentimeters (4 inches) diameter breast height.
Typical—That which normally, usually or commonly occurs (Environmental
Laboratory, 1987).
Under natural conditions—This phrase refers to situations in which plant
species occur in the native state at sites "undisturbed" by man as opposed
to those species occurring as transplants or on sites significantly disturbed
by man's activities (e.g., dredging, filling, draining, and impounding).
Under normal circumstances—This phrase was placed in the regulatory defini-
tion of wetlands to respond, for example, to those situations in which an
individual has attempted to eliminate permit requirements by destroying
the wetland vegetation (e.g., a de-vegetated wetland could normally support
wetland vegetation) and those areas that are not wetlands but experience
the abnormal presence of wetland vegetation (e.g., marsh spoil piles
placed under upland conditions, but temporarily supporting marsh plants
due to remnant plant propagules). Under the former situation, an area
would still remain a part of the overall wetland system protected by the
Section 404 program. Conversely, the abnormal presence of wetland vegetation
in a non-wetland area would not be sufficient to Include that area within
the jurisdiction of the Section 404 program. Legal alterations to the
hydrologlc regime, as opposed to mere removal of vegetation, may alter
"normal circumstances" 1f they 1n fact change the nature of a wetland
area so that it no longer functions as part of waters of the United States.
Understory—As used in this Manual, any herbaceous plant species, Including
bryophytes, occurring at the general ground level. In computing dominance,
however, bryophytes are considered separately.
Uplands—Areas that, under normal circumstances, support a prevalence of
plants that are not typically adapted for life 1n saturated soil conditions.
Uplands include all areas, other than aquatic habitats, that are not
wetlands.
Upland-wetland boundary—The line established 1n jurisdictional determinations
that separate wetland areas from adjacent upland areas.
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A-8
Variant--A unique kind of soil that does not occupy a large enough total area
to warrent the establishment of a new soil series (Soil Survey Staff, in
preparaton).
Vegetation—The plant life as it exists on the ground (i.e., the mosaic of
plant communities on a landscape) (Kuchler, 1967).
Vegetation signature—A unique spectral reflectance or emission response
transmitted or received by a sensor (e.g., the photographic appearance of
vegetation units on color film).
Vegetation structure—The division of a plant community into strata and the
distribution of the various life forms in each of these strata (Kuchler,
1967).
Vegetation unit—A patch, grouping, or zone of plants evident in overall
plant cover which appears distinct from other such units because of the
vegetation's structure and floristic composition. A given unit is typically
topographically distinct and typically has a rather uniform soil, except
possibly for relatively dry microsltes in an otherwise wet area (e.g.,
tree bases, old tree stumps, mosquito ditch spoil piles, and small earth
hummocks) or relatively wet microsltes in an otherwise dry area (e.g.,
small depressions).
Very long duration—A duration class in which inundation for a single event
1s greater than 1 month (Soil Conservation Service, 1987).
Very poorly drained—A condition in which water is removed from the soil so
slowly that free water remains at or on the surface during most of the
growing season (Soil Conservation Service, 1987).
Water table—The zone of saturation at the highest average depth during the
wettest season. It is at least 15 centimeters (6 inches) thick and persists
in the soil for more than a few weeks (Soil Conservation Service, 1987).
Wetland hydrology—The sum total of wetness characteristics in areas that
are inundated or have saturated soils for a sufficient duration to support
hydrophytic vegetation (Environmental Laboratory, 1987).
Wetland indicator status—The exclusiveness or fidelity with which a plant
species occurs in wetlands. The different indicator categories (i.e.,
facultative species, obligate wetland species, and obligate upland species)
are defined elsewhere in this glossary.
Wetlands—Areas that are inundated or saturated by surface or ground water
at a frequency and duration sufficient to support, and that under normal
circumstances do support, a prevalence of vegetation typically adapted for
life in saturated soil conditions. Wetlands generally include swamps, marshes,
bogs and similar areas. (33 CFR Section 328.3 and 40 CFR Section 230.3).
U.S. Environmental Protection Agency
1,1 -""om 2404 PM-211-A
"•01 m Street, S.ff.
Washington, DC 20460
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