Swamp School. Eastern Mountains and Piedmont Region. Hydric Soil and Wetland Hydrology Indicators

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1 Scope Reference Materials The purpose of this procedure is to provide information on the hydric and Wetland Hydrology indicators for the Eastern Mountains and Piedmont Region. This procedure should be used in conjunction with the Swamp s School Wetland Delineation procedure. This information and photographs for all the indicators are taken directly from the US Army Corp of Engineers Regional Supplement for Eastern Mountains and Piedmont Region (version 2.0). The information from the supplement is synthesized to provide basic information on the indicators. Swamp s School Wetland Delineation procedure. This supplement is applicable to the Eastern Mountains and Piedmont Region, which consists of all or portions of the District of Columbia and 20 states: Alabama, Arkansas, Delaware, Georgia, Illinois, Indiana, Kansas, Kentucky, Maryland, Missouri, North Carolina, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, South Carolina, Tennessee, Virginia, and West Virginia. The Atlantic and Gulf Coastal Plain Region is divided into three sub regions that correspond to USDA Land Resource Regions. The following are the portions of those regions that pertain to this procedure: Central and Eastern Mountains (LRR N) Southern Piedmont (MLRA 136 of LRR P) Northern Mountains and Piedmont (MLRAs 147 and 148 of LRR S) Most of the wetland indicators in this procedure are present throughout the entire Atlantic and Gulf Coastal Plain Region. However, some are applicable only to particular sub-regions (LRR) or smaller areas (MLRA).

2 Region Boundaries East of the Mississippi River, the region is bounded by the Atlantic Seaboard Fall Line. The region includes the Mississippi River Embayment. To the west, the region is bounded by the Ouachita Mountains in Arkansas and the eastern edge of the semi-arid Great Plains in Texas. Transitional Areas Climatic conditions and the physical and biological characteristics of landscapes do not change abruptly at the regional and subregional boundaries. These areas grade into one another in broad transition zones. In transitional areas, use experience and good judgment to select the supplement and indicators that are appropriate to the site based on its physical and biological characteristics. If in doubt about which supplement to use in a transitional area, apply both supplements and compare the results. Physical and Biological Characteristics The is an area of hilly to mountainous terrain, ranging from near sea level to 6,684 ft. at Mount Mitchell in North Carolina. Due to its large size and topographic diversity, the region is climatically varied. Wetlands occupy a relatively small percentage of the landscape in the Eastern Mountains and Piedmont Region Hydric Soil Indicators Hydric soils are that which is formed under conditions of saturation, flooding, or ponding long enough during the growing season to develop anaerobic conditions in the upper portion.

3 A1: Histosols: 16 inches or more of the upper 32 inches is organic soil material. 1 In most Histosols, 16 in. or more of the upper 32 in. is organic soil material. Histosols also include soils that have organic soil material of any thickness over rock or fragmental soil material that has interstices filled with organic soil material. Histosol, in which muck (sapric soil material) is greater than 3 ft. thick. the. A2: Histic Epipedon: A histic epipedon underlain by mineral soil material with a Chroma of 2 or less. 2 Most histic epipedons are surface horizons 8 in. or more thick of organic soil material. In this soil, the organic surface layer is about 9 in. thick. the. 3 A3: Black Histic: A layer of peat, mucky peat, or muck 8 inches or more thick that starts within 6 inches of the soil surface; has a hue of 10YR or yellower, value of 3 or less, and Chroma of 1 or less; and is underlain by mineral soil material with a Chroma of 2 or less. A black organic surface layer greater than 11 in. thick. 4 the. A4: Hydrogen Sulfide: A hydrogen sulfide (rotten egg) odor within 12 inches of the soil surface. the.

4 A5: Stratified Layers: Several stratified layers starting within 6 inches of the soil surface. At least one of the layers has a value of 3 or less with a Chroma of 1 or less or it is muck, mucky peat, peat, or mucky modified mineral texture. The remaining layers have chromas of 2 or less. 5 Any sandy material that constitutes the layer with a value of 3 or less and a Chroma of 1 or less, when viewed with a 10- or 15-power hand lens, must have at least 70 percent of the visible soil particles masked with organic material. When viewed without a hand lens, the material appears to be nearly 100 percent masked. Layers in loamy material. Layers in sandy material the. A10:.75 inches of Muck: A layer of muck 0.5 inches or more thick with a value of 3 or less and a Chroma of 1 or less starting within 6 inches of the soil surface. 9 Applicable Subregions: Applicable to the Central and Eastern Mountains Sub region (LRR N). Normally the muck layer is at the soil surface; however, it may occur at any depth within 6 in. of the surface. A layer of muck (dark material indicated by the knife point) occurs in the upper 6 in. of this soil.

5 A11: Depleted Below Dark Surface: A layer with a depleted or gleyed matrix that has 60 percent or more chroma of 2 or less, starting within 12 inches of the soil surface, and having a minimum thickness of either: 6 inches or 2 inches if the 2 inches consists of fragmental soil material. 10 Loamy/clayey layer(s) above the depleted or gleyed matrix must have a value of 3 or less and chroma of 2 or less. Any sandy material above the depleted or gleyed matrix must have a value of 3 or less and chroma of 1 or less. In this soil, a depleted matrix starts immediately below the black surface layer at approximately 11 in. When viewed with a 10- or 15- power hand lens, must have at least 70 percent of the visible soil particles masked with organic material. When viewed without a hand lens, the material appears to be nearly 100 percent masked. the.

6 A12: Thick Dark Surface: A layer at least 6 inches thick with a depleted or gleyed matrix that has 60 percent or more chroma of 2 or less starting below 12 inches of the surface. 11 The layer(s) above the depleted or gleyed matrix must have a value of 2.5 or less and chroma of 1 or less to a depth of at least 12 inches and a value of 3 or less and chroma of 1 or less in any remaining layers above the depleted or gleyed matrix. Deep observations may be required to identify the depleted or gleyed matrix below a thick, dark surface layer. Here the depleted matrix starts at 20 in. Any sandy material above the depleted or gleyed matrix, when viewed with a 10-power or 15-power hand lens, must have at least 70 percent of the visible soil particles masked with organic material. When viewed without a hand lens, the material appears to be nearly 100 percent masked. the. Sandy soils refers to soil materials with a USDA soil texture of loamy fine sand and coarser. Sandy Soils Unless otherwise noted, all mineral layers above any of the layers meeting an S indicator, except for indicator S6, must have a dominant chroma of 2 or less, or the layer(s) with a dominant chroma of more than 2 must be less than 6 in. thick to meet any hydric soil indicator. Nodules and concretions are not considered to be redox concentrations unless otherwise noted.

7 S1: Sandy Mucky Mineral: A layer of mucky modified sandy soil material 2 inches or more thick starting within 6 inches of the soil surface. 1 This indicator is very rare in this region and is most likely found in floodplains. Mucky is a USDA texture modifier for mineral soils. The mucky modified sandy layer is approximately 3 in. thick. Applicable Subregions: Applicable to the Central and Eastern Mountains Sub region (LRR N) and the Northern Mountains and Piedmont Sub region (MLRAs 147 and 148 of LRR S) S4: Sandy Gleyed Matrix: A gleyed matrix that occupies 60 percent or more of a layer starting within 6 inches of the soil surface. 2 There is no thickness requirement for the gleyed layer in this indicator. Gley colors are not synonymous with gray colors. In this example, the gleyed matrix begins at the soil surface. the. 3 S5: Sandy Redox: A layer starting within 6 inches of the soil surface that is at least 4 inches thick and has a matrix with 60 percent or more chroma of 2 or less with 2 percent or more distinct or prominent redox concentrations occurring as soft masses and/or pore linings. Redox concentrations (orange areas) in sandy soil material. the.

8 A diffuse, splotchy pattern of stripped and unstripped areas is revealed in this horizontal slice through a sandy soil. 4 S6: Stripped Matrix: A layer starting within 6 inches of the soil surface in which iron/manganese oxides and/or organic matter have been stripped from the matrix and the primary base color of the soil material has been exposed. The stripped areas and translocated oxides and/or organic matter form a faintly contrasting pattern of two or more colors with diffuse boundaries. The stripped zones are 10 percent or more of the volume and are rounded. the. 5 S7: Dark Surface: A layer 4 in. thick starting within 6 in. of the soil surface with a matrix value of 3 or less and chroma of 1 or less. the. This sandy soil has a dark surface approximately 6 in. thick.

9 In this soil, the splotchy pattern below the dark surface is due to mobilization and translocation of organic matter. 6 S8: Poly Value Below Surface: A layer with a value of 3 or less and chroma of 1 or less starting within 6 in. of the soil surface Applicable Subregions: Applicable to the Northern Mountains and Piedmont Sub region (MLRAs 147 and 148 of LRR S) 7 Indicator S9: Thin Dark Surface: A layer 2 in. or more thick starting within the upper 6 in. of the soil, with a value of 3 or less and chroma of 1 or less. Applicable Subregions: Applicable to the Northern Mountains and Piedmont Sub region (MLRAs 147 and 148 of LRR S) Example of the Thin Dark Surface indicator. A spodic horizon is present starting at 8 in.

10 Loamy and Clayey Soils Loamy and clayey soils refers to soil materials with USDA textures of loamy very fine sand and finer. Use the following indicators in soil layers consisting of loamy or clayey soil materials. Unless otherwise noted, all mineral layers above any of the layers meeting an F indicator, except for indicators F8, F12, and F19, must have a dominant chroma of 2 or less, or the layer(s) with a dominant chroma of more than 2 must be less than 6 in. (15 cm) thick to meet any hydric soil indicator. Nodules and concretions are not considered to be redox concentrations unless otherwise noted. 2 Indicator F2: Loamy Gleyed Matrix: A gleyed matrix that occupies 60 percent or more of a layer starting within 12 in. of the soil surface. the. This soil has a gleyed matrix in the lowest layer, starting about 7 in. from the soil surface. The layer above the gleyed matrix has a depleted matrix.

11 This soil has a depleted matrix with redox concentrations in a low-chroma matrix. 3 Indicator F3: Depleted Matrix: A layer with a depleted matrix that has 60 percent or more chroma of 2 or less and that has a minimum thickness of either: 2 in. if the 2 in. is entirely within the upper 6 in. of the soil, or 6 in. starting within 10 in. of the soil surface. the. Example of indicator Depleted Matrix in which redox concentrations extend nearly to the surface. 4 Indicator F6: Redox Dark Surface: A layer that is at least 4 in. thick, is entirely within the upper 12 in. of the mineral soil, and has a: Matrix value of 3 or less and chroma of 1 or less and 2 percent or more distinct or prominent redox concentrations occurring as soft masses or pore linings, or Matrix value of 3 or less and chroma of 2 or less and 5 percent or more distinct or prominent redox concentrations occurring as soft masses or pore linings. Redox features can be small and difficult to see within a dark soil layer. the.

12 Indicator F7: Depleted Dark Surface: Redox depletions with a value of 5 or more and chroma of 2 or less in a layer that is at least 4 in. thick, is entirely within the upper 12 in. of the mineral soil and has a: 5 Matrix value of 3 or less and chroma of 1 or less and 10 percent or more redox depletions, or Matrix value of 3 or less and chroma of 2 or less and 20 percent or more redox depletions. the. Redox depletions (lighter colored areas) are scattered within the darker matrix. 6 Indicator F8: Redox Depressions: In closed depressions subject to ponding, 5 percent or more distinct or prominent redox concentrations occurring as soft masses or pore linings in a layer that is 2 in. or more thick and is entirely within the upper 6 in. of the soil. the. In this example, the layer of redox concentrations begins at the soil surface and is slightly more than 2 in. thick.

13 Indicator F12: Iron-Manganese Masses: On floodplains, a layer 4 in. or more thick with 40 percent or more chroma of 2 or less and 2 percent or more distinct or prominent redox concentrations occurring as soft iron- manganese masses with diffuse boundaries. 9 The layer occurs entirely within 12 in. of the soil surface. Iron-manganese masses have a value and chroma of 3 or less. Most commonly, they are black. The thickness requirement is waived if the layer is the mineral surface layer. Iron-manganese masses (black spots) in a 40-percent depleted matrix. Applicable to the Central and Eastern Mountains Sub region (LRR N) and the Southern Piedmont Sub region (MLRA 136 of LRR P) This umbric surface is approximately 12 in. thick. 10 Indicator F13: Umbric Surface: In depressions and other concave landforms, a layer 10 in. or more thick starting within 6 in. of the soil surface in which the upper 6 in. has a value of 3 or less and chroma of 1 or less and in which the lower 4 in. has the same colors as those described above or any other color that has a chroma of 2 or less. Applicable Subregions: Applicable to the Southern Piedmont Sub region (MLRA 136 of LRR P) and MLRA 122 in the Central and Eastern Mountains Sub region (LRR N) Location of MLRA 122 in LRR N.

14 Location of MLRA 148 in LRR S. 13 Indicator F19: Piedmont Floodplain Soils: On active floodplains, a mineral layer at least 6 in. thick starting within 10 in. of the soil surface with a matrix (60 percent or more of the volume) chroma of less than 4 and 20 percent or more distinct or prominent redox concentrations occurring as soft masses or pore linings. Applicable Subregions: Applicable Subregions: Applicable to the Northern Piedmont (MLRA148 of LRR S) The Piedmont Floodplain Soils indicator is restricted to floodplains that are actively receiving sediments and groundwater discharge with high iron content.

15 Indicator F21: Red Parent Material: A layer at least 4 inches thick, starting 10 inches of the soil surface with a hue of 7.5YR or redder. The matrix has a value and chroma greater than 2 and less than or equal to 4. Location of MLRA 127 in LRRN, MLRA 147 in LRR S, and MLRA 148 in LRR S. The layer must contain 10 percent or more distinct or prominent redox concentrations occurring as soft masses or pore linings and/or depletions. Redox depletions should differ in color by having: Value one or more higher and chroma one or more lower than the matrix, or Value of 4 or more and chroma of 2 or less. Approximate locations of soils derived from red parent materials (red areas) in the Eastern Mountains and Piedmont Region. Applicable Subregions: For use in MLRA 147 and 148 of LRR S and MLRA 127 of LRR N; for testing in all soils derived from red parent materials. Problem Soils These indicators may be used in problem wetland situations in the Eastern Mountains and Piedmont Region where there is evidence of wetland hydrology and hydrophytic vegetation, and the soil is believed to meet the definition of a hydric soil despite the lack of other indicators of a hydric soil.

16 1 Indicator A10: Muck: A layer of muck 0.75 in. or more thick with value of 3 or less and chroma of 1 or less, starting within 6 in. of the soil surface. Applicable Subregions: For use with problem soils in the Northern Appalachian Ridges and Valleys (MLRA 147 of LRR S). 2 Indicator A16: Coast Prairie Redox: A layer starting within 6 in. of the soil surface that is at least 4 in. thick and has a matrix chroma of 3 or less with 2 percent or more distinct or prominent redox concentrations occurring as soft masses and/or pore linings. Applicable Subregions: For use with problem soils in the Northern Mountains and Piedmont Sub region (MLRAs 147 and 148 of LRR S) 3 Indicator F19: Piedmont Floodplain Soils: On active floodplains, a mineral layer at least 6 in. thick starting within 10 in. of the soil surface with a matrix (60 percent or more of the volume) chroma of less than 4 and 20 percent or more distinct or prominent redox concentrations occurring as soft masses or pore linings. Applicable Subregions: For use with problem soils on floodplains in the Southern Piedmont Sub region (MLRA 136 of LRR P) and the Northern Appalachian Ridges and Valleys (MLRA 147 of LRR S)

17 Indicator TF12: Very Shallow Dark Surface: In depressions and other concave landforms, one of the following: 3 a. If bedrock occurs between 6 in. and 10 in., a layer at least 6 in. thick starting within 4 in. of the soil surface with a value of 3 or less and chroma of 1 or less, and the remaining soil to bedrock must have the same colors as above or any other color that has a chroma of 2 or less. b. If bedrock occurs within 6 in., more than half of the soil thickness must have a value of 3 or less and chroma of 1 or less, and the remaining soil to bedrock must have the same colors as above or any other color that has a chroma of 2 or less. Applicable Subregions: For use with problem soils throughout the Eastern Mountains and Piedmont Region.

18 A2 Hydrology Indicators Wetland hydrology indicators are presented in four groups. Indicators in Group A are based on the direct observation of surface water or groundwater during a site visit. Group B consists of evidence that the site is subject to flooding or ponding, although it may not be inundated currently. Group C consists of other evidence that the soil is saturated currently or was saturated recently. Group D consists of landscape, vegetation, and soil features that indicate contemporary rather than historical wet conditions. Within each group, indicators are divided into two categories primary and secondary based on their estimated reliability in this region. Group: Surface water 1 A1: Surface Water: A visual verification of surface water (flooding or ponding). the.

19 Group: Surface water or saturated soils 2 A2: High Water Table: Locate a soil pit, auger hole or monitoring well within the sample plot. Measure the water table depth; a measurement of 12 inches or less, from the surface, is a positive indication. High water table observed in a soil pit the. Group: Surface water or saturated soils 3 A3: Saturation: Observation of saturated soil conditions 12 inches or less from the soil surface as indicated by water glistening on the surfaces and broken interior faces of soil samples removed from the pit or auger hole. Water glistens on the surface of a saturated soil sample. the. Group: Recent Inundation 4 B1: Water Marks: Discolorations or stains on the bark of wood vegetation, rocks, bridge supports, buildings, fences, or other fixed objects as a result of flooding. Water marks (dark stains) on trees in a seasonally flooded wetland. The top of one water mark is indicated by the arrow. the.

20 Group: Recent Inundation 5 B2- Sediment Deposits: Found after surface water recedes. Layers of fine-grained mineral material or organic material found remaining on tree bark, plant stems/leaves, rocks, and other objects. Silt deposit left after a recent high-water event forms a tan coating on these tree trunks (upper edge indicated by the arrow). the. Group: Recent Inundation 6 B3- Drift Deposits: consists of remnants of vegetation, man-made litter, or other waterborne materials. Occurs when rafted debris is deposited or entangled in vegetation or other fixed objects. Drift deposit in a floodplain wetland. the.

21 Dried algal crust in a forested wetland 7 Group: Recent Inundation B4- Algal mat or crust: Mat or dried crust of algae, perhaps mixed with other detritus, left on or near the soil surface after dewatering. Algal deposits include those produced by green algae (Chlorophyta) and blue-green algae (cyanobacteria). They may be attached to low vegetation or other fixed objects, or may cover the soil surface. the. Crust of blue-green algae on the soil surface.

22 Group: Recent Inundation Iron sheen on the water surface may be deposited as an orange or yellow crust after dewatering. 8 B5- Iron Deposits: A thin yellow or orange crust or gel of oxidized iron on the soil surface Iron deposits form in areas where reduced iron discharges with groundwater and oxidizes upon exposure to air. The oxidized iron forms a film or sheen on standing water and an orange or yellow deposit on the ground surface after dewatering. the. Iron deposit (orange streaks) in a small channel. Group: Recent Inundation Forested wetland with surface water present. 9 B7-Inundation visible on aerial images: when one or more recent aerial photographs or satellite images shows a site to be inundated. Care must be used in applying this indicator because surface water may be present on a nonwetland site immediately after a heavy rain or during periods of unusually high precipitation, runoff, tides, or river stages. the.

23 Group: Recent Inundation 10 B9- Water-stained leaves: Water-stained leaves are fallen or recumbent dead leaves that have turned grayish or blackish in color due to inundation for long periods. Water-stained leaves in a depressional wetland (unstained leaf for comparison). the. Group: Recent Inundation Amphibian tadpoles trapped in a drying pool in a wet meadow. 11 B13- Aquatic fauna: Presence of live individuals, diapausing insect eggs or crustacean cysts, or dead remains of aquatic fauna, such as, but not limited to, sponges, bivalves, aquatic snails, aquatic insects, ostracods, shrimp, other crustaceans, tadpoles, or fish, either on the soil surface or clinging to plants or other emergent objects. the. Shells of aquatic snails in a seasonally ponded wetland.

24 Group: Recent Inundation Indicator B14: True aquatic plants: This indicator consists of the presence of live individuals or dead remains of true aquatic plants. Dried remains of waterlilies in a semi permanently ponded wetland. the. Group: Recent Inundation Category: Secondary 13 B6-Surface soil cracks: inspect the surface soil for shallow cracks formed from dried and shrunken fine-grained mineral or organic sediments that have created cracks or small polygons. Surface soil cracks in a seasonally ponded depression. the.

25 Group: Recent Inundation Category: Secondary 14 B8 - Sparsely vegetated concave surface: On concave land surfaces the ground surface is either not vegetated or sparsely vegetated due to longduration ponding or flooding during the growing season. the. A sparsely vegetated, seasonally ponded depression

26 Drainage patterns seen during a flooding event. The patterns are also evident when the wetland is dry. 15 Group: Recent Inundation Category: Secondary B10 - Drainage Patterns: This indicator consists of flow patterns visible on the soil surface or eroded into the soil, low vegetation bent over in the direction of flow, absence of leaf litter or small woody debris due to flowing water, and similar evidence that water flowed across the ground surface. Drainage patterns are usually seen in areas where water flows broadly over the surface or in a braided pattern and is not confined to a channel, such as in areas adjacent to streams, in seeps, slope wetlands, vegetated swales, and hardwood flats the. Vegetation bent over in the direction of water flow across a stream terrace.

27 Group: Recent Inundation Category: Secondary 16 B16- Moss trim lines: Presence of moss trim lines on trees or other upright objects in seasonally inundated areas. the. Moss trim lines in a seasonally flooded wetland. Trim lines indicate a recent high-water level. Group: Evidence of current or recent soil saturation 17 C1- Hydrogen Sulfide Odor: Hydrogen sulfide (rotten egg) odor within 12 in. of the soil surface the.

28 Iron-oxide plaque (orange coating) on a living root. Iron also coats the channel or pore from which the root was removed. 18 Group: Evidence of current or recent soil saturation C3- Oxidized rhizospheres along living roots: A layer containing 2% or more iron-oxide coatings/plaques on the surface of a living root and/or iron-oxide coatings/linings on soil pores, surrounding living roots within 12 inches of the soil surface. the. This soil has many oxidized rhizospheres associated with living roots.

29 Group: Evidence of current or recent soil saturation 19 C4- Presence of reduced iron: A layer of reduced (ferrous) iron in the upper 12 in. of the soil profile, as indicated by the ferrous iron test or presence of soil that changes color upon air exposure. The reduction of iron occurs in soils that have been saturated long enough to become anaerobic and chemically reduced. When alpha, alpha-dipyridyl is applied to a soil containing reduced iron, a positive reaction is indicated by a pink or red coloration to the treated area. the. Group: Evidence of current or recent soil saturation 20 C6- Recent iron reduction in tilled soils: Presence of a layer that contains 2% or more redox concentrations as pore linings or soft masses in the tilled surface layer of soil cultivated in the last two years. Redox concentrations in the tilled surface layer of a recently cultivated soil. the. Group: Evidence of current or recent soil saturation 21 C7- Thick muck surface: Consists of a layer of muck 1 in. or less thick on the soil surface. the.

30 Group: Evidence of current or recent soil saturation Category: Secondary 22 C2- Dry-season water table: visual observation of the water table between 12 and 24 in. below the surface during the normal dry season or during a drier year. the. Group: Evidence of current or recent soil saturation Category: Secondary 23 C8- Crayfish burrows: Presence of crayfish burrows, 2 in. diameter openings in the soft ground, often surrounded by chimney-like mounds of mud. Crayfish burrow in a saturated wetland. the. Group: Evidence of current or recent soil saturation Category: Secondary 24 C9- Saturation visible on aerial imagery: One or more recent aerial photographs or satellite images indicate soil saturation. Aerial photograph of an agricultural field with saturated soils indicated by darker colors. the.

31 Stunted and yellowed corn due to wet spots in an agricultural field Group: Evidence from other site conditions/data. Category: Secondary D1: Stunted or stressed plants- In agricultural or planted vegetation located in a depression, swale, or other topographically low area, this indicator is present if individuals of the same species growing in the potential wetland are clearly of smaller stature, less vigorous, or stressed compared with individuals growing in nearby drier landscape situations. Group: Evidence from other site conditions/data. Category: Secondary D2- Geomorphic position: Is present if the area in question is in a depression, linear drainage way, concave position within a floodplain, at the toe of a slope, on the low-elevation fringe of a pond/body of water, or in an area where groundwater discharges. the. 26 Group: Evidence from other site conditions/data. Category: Secondary D3- Shallow Aquitard: Occurs in and around depressions and flat landscapes. Consists of the presence of an aquitard within the soil profile that is potentially capable of perching water within 12 in. of the surface. the.

32 Group: Evidence from other site conditions/data. Category: Secondary 27 D4- Micro Topographic Relief: Consists of the presence of micro topographic features that occur in areas of seasonal inundation or shallow water tables (like hummocks or tussocks). the. This hemlock-dominated wetland has trees growing on hummocks and herbaceous plants growing in tussocks Group: Evidence from other site conditions/data. Category: Secondary 28 D5- FAC neutral test: The plant community passes the FAC-neutral test. the.