Wetland Classification and Assessment

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Wetland Classification and Assessment
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Why the emphasis on wetlands

• Wetlands are aquatic systems that has been and
  continues to be lost at a rapid rate
• These ecosystems provide numerous ecological
  services that would cost the public significant
  amounts of money to duplicate
• Many entities (including the public) do not
  understand their value
• Large numbers of our endangered species are
  located in wetlands

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Wetland delineation

• Many federal, state, and local agencies, private
  organizations, and landowners need to identify or
  delineate the boundaries of wetlands for a
  variety of purposes
• Each agency may be required to use one or more
  federal, state, or local laws or guidelines
  defining wetlands in specific ways.

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Who has responsibilities for wetlands

• U.S. Army Corps of Engineers (Corps) administers
  the Section 404 program governing the discharge
  of dredge and fill material into waters in the
  U.S. as defined and guided by Section 404 of the
  Clean Water Act.
• The wetlands which fall within the Section 404
  regulation are referred to as jurisdictional
  wetlands.
• The U.S. Fish and Wildlife Service scientists and
  many other scientists, land use planners, and
  watershed or water quality managers, utilize the
  Cowardin system for more in-depth identification
  or classification of wetlands.

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What you already know about wetland
classification

• Cowardin Wetland and Deepwater Systems
• The following is a brief description of the major
  classes of wetlands under the Cowardin system.
  Marine - Open ocean overlying the continental
  shelf and coastline exposed to waves and currents
  of the open ocean shoreward to (1) extreme high
  water of spring tides (2) seaward limit of
  wetland emergents, trees, or shrubs or (3) the
  seaward limit of the Estuarine System, other than
  vegetation. Salinities exceed 30 parts per
  thousand (ppt).
• Estuarine - Deepwater tidal habitats and adjacent
  tidal wetlands that are usually semi-enclosed by
  land but have open, partly obstructed, or
  sporadic access to the ocean, with ocean-derived
  water at least occasionally diluted by freshwater
  runoff from the land. The upstream and landward
  limit is where ocean-de rived salts measure less
  than .5 ppt during the period of average annual
  low flow. The seaward limit is (1) an imaginary
  line closing the mouth of a river, bay, or sound
  and (2) the seaward limit of wetland emergents,
  shrubs, or trees when not included in (1).
• Riverine - All wetlands and deepwater habitats
  contained within a channel except those wetlands
  (1) dominated by trees, shrubs, persistent
  emergents, emergent mosses, or lichens, and
  (2)which have habitats with ocean-derived
  salinities in excess of .5 ppt.
• Lacustrine - Wetlands and deepwater habitats (1)
  situated in a topographic depression or dammed
  river channel (2) lacking trees, shrubs,
  persistent emergents, emergent mosses, or lichens
  with greater than 30 areal coverage and
  (3)whose total area exceeds 8 hectares (20
  acres) or area less than 8 hectares if the
  boundary is active wave-formed or bedrock or if
  water depth in the deepest part of the basin
  exceeds 2 m (6.6 ft) at low water. Ocean-derived
  salinities are always less than .5 ppt.
• Palustrine - All nontidal wetlands dominated by
  trees, shrubs, persistent emergents, emergent
  mosses, or lichens, and all such tidal wetlands
  where ocean-derived salinities are below .5 ppt.
  This category also includes wetlands lacking such
  h vegetation but with all of the following
  characteristics (1) area less than 8 ha (2)
  lacking an active wave-formed or bedrock
  boundary (3) water depth in the deepest part of
  the basin less than 2 m (6.6 ft) at low water
  and (4) ocean-derived salinities less than .5
  ppt.
• A Palustrine system can exist directly adjacent
  to or within the Lacustrine, Riverine, or
  Estuarine systems.

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What you already know about wetland
classification

• Wetland indicators of deliniation
• Hydric plants (hydrophytic vegetation)
• Hydrology
• Hydric soils

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Hydric plants

• Criteria for a wetland more than 50 of the
  composition of the dominant species (largest
  relative basal area (trees), greatest height
  (woody understory), number of stems (vines) or
  greatest areal cover (herbaceous understory) from
  all strata (overstory, understory, woody vines,
  ground cover/herbaceous understory), must be
  obligate wetland (OBL) species, facultative
  wetland species (FACW), and/or facultative (FAC)
  species.
• Obligate wetland species (OBL) occur more than
  99 of the time only in wetlands.
• Facultative Wetland species (FACW) occur in
  wetlands 67-99 of the time.
• Facultative species (FAC) are tolerant of wet and
  dry conditions. They are as likely to occur in
  uplands as in wetlands and are found in wetlands
  34-66 of the time.

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Morphological adaptations to permanent or
periodic inundation or soil saturation and
examples of species displaying adaptations

• Buttressed tree trunk Taxodium distichum (Bald
  cypress), (swollen bases) Nyssa (Gum)
• Multiple trunks (Acer rubrum) Red maple
• Pneumatophores (knees) Taxodium distichum,
  Nyssa aquatica Stubby projections extending from
  the roots to heights above the average water
  level.
• Adventitious Roots Plantanus occidentalis
  (Sycamore), Salix Roots occurring on plant
  (Willow), Ludwigia (Water primrose) stems and
  above soil surface.
• Shallow roots (exposed) Acer rubrum (Red maple)
• Hypertrophied lenticels Salix (Willows), Acer
  rubrum (Red maple) Large lenticels, allowing
  greater gas exchange Aerenchyma in roots and
  stems Juncus spp. (Rush), Typha spp. (Cattails),
  spongy, air filled tissue Cyperus spp. (Sedges)
• Polymorphic leaves Sagittaria (Arrowheads),
  Leaves that have different shapes depending on
  site conditions
• Floating leaves White water lily,

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Hydrology

• Wetlands require permanent or periodic inundation
  or soil saturation at the surface for a week or
  more during the growing season to be a wetland
  ecologically as well as for jurisdictional
  purposes.
• These conditions create an anaerobic environment
  which affects the plants and soil.
• Hydrology is not as useful for wetland
  identification as the use of vegetation and soil
  characteristics since many wetlands are dry for
  much of the year.
• Hydrology is a feature of the regulatory
  determination of "jurisdictional wetlands" but is
  considered "technically flawed" by experts in the
  field of delineation who recommend that only
  vegetation and soil characteristics be used
  (Tiner 1993 Day et al. 1993).
• However, if obligate species comprise all
  dominants in the community and there has been no
  recent significant hydroperiod alteration, the
  hydrology characteristic is fulfilled for
  jurisdictional wetland delineation even if no
  water is present.

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Hydric soils

• Hydric soils take time to form, and are formed
  from regular or constant water saturation or
  inundation.

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Hydric soils include

• 1. All Histosols except Folists,
• Histosols are organic soils (more than 50 of
  upper 32 inches by volume is organic) or any
  depth of organic material on bedrock Folists are
  non hydric organic soils originating from
  excessive moisture in tropical and boreal
  mountains.
• or,
• 2. Soils in Aquic suborders and Aquic subgroups
  that are
• Somewhat poorly drained and water table lt0.5 ft
  from the surface (gt1 week during the growing
  season.
• Poorly drained or very poorly drained and have
  either
• Water table lt1 ft from the surface for (gt1 week
  during the growing season if permeability (6
  in/hr in all layers within 20 inches of the
  surface
• Water table lt 1.5 ft from the surface for (gt1
  week during the growing season if permeability lt6
  in/hr in all layers within 20 inches of the
  surface.
• Soils that are ponded for long duration (or
  inundation by a single event for (7 days) during
  the growing season.
• Soils that are frequently flooded (gt 50
  probability of flooding in a given year) for long
  duration during the growing season.

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Field indicators of hydric soils

• These are listed in the order in which they can
  be used to definitively indicate whether soils
  are hydric and the area is a wetland.
• Histosols (except Folists)
• Histic epipedon
• Sulfidic materials (H2S) in mineral soils
  emitting the smell of rotten eggs
• Aquic moisture regime (usually hydric soil) or
  peraquic moisture regime
• Reducing soil conditions as indicated by
• Gleyed soils (blueish or greenish gray)
  immediately below A horizon, matrix chroma
  (predominant color) less than or equal to 1
  (using Munsell Soil Color Book)
• Bright mottles immediately below A horizon or 10
  inches and/or matrix chroma of less than or equal
  to 2 (if soil has mottles color determined with
  wet or moist soils)
• Iron (reddish brown) and/or manganese (black)
  concretions
• always hydric soils

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Field indicators of wetland hydrology

• visual observation of inundation
• visual observation of soil saturation in 18" hole
  to 12" depth
• watermarks (stains on bark or other fixed
  objects)
• water-borne debris deposition, particularly in
  aboveground vegetation
• water-borne sediment deposits on plants and other
  vertical objects
• drainage patterns within wetlands, including
  scouring
• water stained (blackened or grey) leaves

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Field Indicators of Hydric Soils

• There are several field indicators that can help
  in determining if a soil would be considered
  hydric, including
• Organic Soils
• Are easily recognized as thick peats and mucks.
  Mucks feel greasy when rubbed between the
  fingers. Partially decomposed plant remains can
  be identified in
• peats.
• Organic Surface Layer
• Organic surface layers often form above the
  mineral substrate in hydric mineral soils due to
  the greatly slowed decomposition of the organic
  matter as a result of soil saturation and
  inundation.

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Field Indicators of Hydric Soils

• Sulfidic Material
• Soils that emit an odor of rotten eggs indicate
  permanent saturation and the presence of sulfidic
  material. Such permanent saturation causes
  anaerobic conditions that cause the sulfidic
  material to be chemically reduced to form
  hydrogen sulfide.
• Soil Color
• Due to the presence of water in the soil column
  creating very low oxygen conditions, hydric
  mineral soils often form diagnostic colors. The
  two main categories of hydric soil colors are
  gleyed and low chroma/mottled soils. Gleying
  (bluish, greenish, or grayish colors) is an
  indication of a soil that is saturated for
  prolonged periods. Low chroma (dull) colors and
  mottles (bright splotches of color in a dull
  matrix) indicate soils that are alternately
  saturated and unsaturated during the growing
  season. Accurately identifying soil colors
  usually requires comparing the soil to
  standardized color charts made specifically for
  that purpose.

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Field Indicators of Hydric Soils

• Dark Vertical Streaking
• In sandy soils with an organic surface layer,
  organic matter is moved downward through the sand
  as the water table fluctuates. This often occurs
  more rapidly in some sections of the soil than in
  others. As a result, a cross-sectional view of
  the soil as revealed in a soil pit will appear to
  be vertically streaked. (It is important to note
  that some non-hydric soils may also reveal
  vertical streaking.)
• Iron and Manganese Concretions
• Under the chemical conditions of hydric soils,
  iron and manganese are sometimes segregated into
  concretions or soft masses. These accumulations
  are usually black or dark brown.

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Aids for identification of wetlands

• U.S. Geological Survey (USGS) Topographic Maps
• National Wetlands Inventory
• http//www.fws.gov/wetlands/
• USDA Soil Conservation Service Soil Surveys and
  Hydric Soils List
• http//www.nrcs.usda.gov/

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Helping the public understand wetlands

• Do I Have A Wetland On My Property?
• Many property owners are confused about the
  technical definitions of wetlands.
• This is understandable given the variety of
  wetlands in Michigan and the fact that many
  wetland types look different than our traditional
  conception of a wetland (which is typically a
  cattail marsh). Below are a few questions that
  you can ask yourself about your land that relate
  to the information in this chapter. A YES answer
  to any of the questions may indicate that you
  have a wetland on your property.

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Helping the public understand wetlands

• YES NO
• n n Is the ground soggy underfoot in the
  spring?
• n n Are there depressions where water
  pools on the ground surface during
• the spring?
• n n Do you avoid the area with heavy
  equipment for fear of getting stuck?
• n n Would you need to ditch the site to
  dry it out?
• n n Is the site in a depression that has
  a different vegetation community than the higher
  ground
• around it?
• n n Are there groundwater seeps or
  springs present?
• n n Are fallen leaves black or very
  darkly stained and contain sediment deposits on
  their surfaces?
• n n Dig a hole. Is the soil gray, or
  contain bright mottles (red or orange) against a
  gray background?
• n n If farmed, is there crop stress due
  to excessive water?
• n n Does the National Wetland Inventory
  map, U.S.G.S. topographical show a wetland on
  your property?
• n n Does the NRCS Soil Survey for your
  county show the soil on your property to be
  hydric, poorly, or very poorly drained?