| Code | Description |
| Aquatic bed | Includes wetlands and deepwater habitats dominated by plants that grow principally on or below the surface of the water for most of the growing season in most years. Water regimes include subtidal, irregularly exposed, regularly flooded, permanently flooded, intermittently exposed, semipermanently flooded, and seasonally flooded. The plants are either attached to the substrate or float freely above the bottom or on the surface. |
| Aquatic bed, All subclasses | See AB1-6 for information. |
| Aquatic bed, Algal | Occur in both the Subtidal and Intertidal subsystems and may grow to depths of 30 m (98 feet). Inland, the stonewarts Chara, Nitella, and Tolypella are examples of algae that look much like vascular plants and may grow in similar situations. Other algae bearing less resemblance to vascular plants are also common. Mats of filamentous algae may cover the bottom in dense blankets, may rise to the surface under certain conditions, or may become stranded on Unconsolidated or Rocky Shores. |
| Aquatic bed, Aquatic Moss | Aquatic mosses are far less abundant than algae or vascular plants. They occur primarily in the Riverine System and in permanently flooded and intermittently exposed parts of some Lacustrine Systems, or at depths as great as 120m (394 ft). For simplicity, aquatic liverworts of the genus Marsupella are included in this subclass. |
| Aquatic bed, Rooted Vascular | Rooted Vascular aquatic plants occur at all depths within the photic zone. They often occur in sheltered areas where there is little water movement or in the flowing water of the Riverine System, where they may be streamlined or flattened in response to high water velocities. The riverweed (Podostemum ceratophyllum) is included in this class despite its lack of truly recognizable roots. Some of the Rooted Vascular species are characterized by floating leaves. Typical dominants include water lilies (Nymphaea, Nuphar), floating-leaf pondweed (Potamogeton natans), and water shield (Brasenia schreberi). Plants such as the yellow water lily and water smartweed which may stand erect above the water surface or substrate, may be condidered either emergents or Rooted Vascular aquatic plants, depending on the life form adopted at a particular site. |
| Aquatic bed, Floating Vascular [not rooted] | The plants float freely either in the water or on its surface. Plants that float on the surface are found primarily in protected portions of slow-flowing rivers and in the Lacustrine and Palustrine systems. They are easily moved about by wind or water currents and can cover a large area of water. |
| Aquatic bed, Unknown Submergent | |
| Aquatic bed, Unknown Surface | |
| Beach/bar | Beach: a sloping landform on the shore of larger water bodies, generated by waves and currents and extending from the water to a distinct break in landform or substrate type. Bar: an elongated landform generated by waves and currents, usually running parallel to the shore, composed predominantly of unconsolidated sand, gravel, stones, cobbles, or rubble and with water on two sides. |
| Beach/bar, all subclasses | |
| Beach/bar, cobble/gravel | |
| Beach/bar, sand | |
| Emergent | Characterized by erect, rooted, herbaceous hydrophytes, excluding mosses and lichens. This vegetation is present for most of the growing season in most years and are usually dominated by perennials. All water regimes are included except subtidal and irregularly exposed. Common names include marsh, meadow, fen, prairie pothole, and slough. Areas that are dominated by pioneer plants that become established during periods of low water are not Emergent Wetlands and should be classified as Vegetated Unconsolidated Shores or Vegetated Streambeds. |
| Emergent, All subclasses | See EM1-6 for information |
| Emergent, Persistent | Dominated by species that normally remain standing at least until the beginning of the next growing season. This subclass is found only in the Estuarine and Palustrine systems. |
| Emergent, Nonpersistent | Dominated by plants which fall to the surface of the substrate or below the surface of the water at the end of the growing season so that, at certain seasons of the year, there is no obvious sign of emergent vegetation. Movement of ice often removes all traces of emergent veg., where this occurs it should be classified as Nonpersistent. |
| Emergent, Narrow-leaved nonpersistent | |
| Emergent, Broad-leaved nonpersistent | |
| Emergent, Narrow-leaved persistent | |
| Emergent, Broad-leaved persistent | |
| Flat | A level land form composed of unconsolidated sediments usually mud or sand. Flats may be irregularly shaped or elongate and continuous with the shore, whereas bars are generally elongate, parallel to the shore, and separated from the shore by water. |
| Flat, all subclasses | |
| Flat, cobble/gravel | |
| Flat, sand | |
| Flat, mud | |
| Flat, organic | |
| Flat, vegetated pioneer | |
| Flat, vegetated nonpioneer | |
| Forested | The class Forested Wetland is characterized by woody vegetation that is 6m tall or taller. They occur only in the Palustrine; all water regimes are included except subtidal. Most common where moisture is relatively abundant, along rivers and in the mountains. |
| Forested, All subclasses | See FO1-7 for information. |
| Forested, Broad-leaved deciduous | Examples are red maple, ashes, black gum, tupelo gum, etc. These wetlands are most common in the Southeast. |
| Forested, Needle-leaved deciduous | Examples are Bald and pond cypress, Tamarack. |
| Forested, Broad-leaved evergreen | Most prominant in the Southeast. Examples are red bay, loblolly bay, sweet bay, and mangroves. |
| Forested, Needle-leaved evergreen | Examples are Black spruce of the North, Northern Black cedar, Atlantic white cedar, and pond pine of the southeast. |
| Forested, Dead | Dead woody vegetation taller than 6m (20 ft). |
| Forested, Deciduous | Deciduous trees or shrubs represent more than 50% of total areal coverage of trees and shrubs. |
| Forested, Evergreen | Evergreen trees or shrubs represent more than 50% of total areal coverage of trees and shrubs. |
| Moss/lichen | Includes areas where mosses or lichens cover substrates other than rock and where emergents, shrubs, or trees make up less than 30% of the areal cover. The only water regime is saturated. These wetlands are not common even in the North where they occur most frequently. |
| Moss/lichen, All subclasses | See ML1 and 2 for information |
| Moss/lichen, Moss | Moss wetlands are most abundant in the far north. |
| Moss/lichen, Lichen | Lichen wetlands are also a northern subclass. |
| Open water, Unknown bottom | |
| Rock bottom | The class Rock Bottom includes all wetlands and deepwater habitats with substrates having an areal cover of stones, boulders, or bedrock 75% or greater and vegetative cover of less than 30%. Water regimes are restricted to subtidal, permanently flooded, intermittently exposed, and semipermanently flooded. |
| Rock bottom, All subclasses | See RB1 and 2 for information. |
| Rock bottom, Bedrock | Bottoms in which bedrock covers 75% or more of the surface. (See RB., RB0 for more information.) |
| Rock bottom, Rubble | Rubble. - Bottoms with less than 75% areal cover of bedrock, but stones and boulders alone, or in combination with bedrock, cover 75% or more of the surface. |
| Rocky shore | Includes wetland environments characterized by bedrock, stones, or boulders which singly or in combination have an areal cover of 75% or more and an areal coverage by vegetation of less than 30%. Water regimes are restricted to irregularly exposed, regularly flooded, irregularly flooded, seasonally flooded, temporarily flooded, and intermittently flooded. In the Lacustrine and Riverine systems, Rocky Shores support sparse plant and animal communities. |
| Rocky shore, All subclasses | Each zone supports a rich assemblage of invertebrates, and algae or lichens or both. If aquatic liverworts or mosses cover 30% or more of the substrate, they should be placed in the class Aquatic Bed. (See RS1-3 for information.) |
| Rocky shore, Bedrock | These wetlands have bedrock covering 75% or more of the surface and less than 30% areal coverage of macrophytes. |
| Rocky shore, Rubble | These wetlands have less than 75% areal cover of bedrock, but stones and boulders alone or in combination with bedrock cover 75% or more of the area. The areal coverage of macrophytes is less than 30%. |
| Rocky shore, Vegetated nonpioneer | |
| Streambed | Includes all wetland contained within the Intermittent Subsystem of the Riverine System. Water regimes are restricted to irregularly exposed, regularly flooded, irregularly flooded, seasonally flooded, temporarily flooded, and intermittently flooded. In most cases streambeds are not vegetated because of the scouring effect of moving water, but, like Unconsolidated Shores, they may be colonized by "pioneering" annuals or perennials during periods of low flow or they may have perennial emergents and shrubs that are too scattered to qualify the area for classification as Emergent Wetland or Scrub-Shrub Wetland. |
| Streambed, All subclasses | See SB1-4 for information |
| Streambed, Bedrock | Characterized by a bedrock substrate covering 75% or more of the stream channel. It occurs most commonly in the Riverine System in high mountain areas or in glaciated areas where bedrock is exposed. |
| Streambed, Rubble | Characterized by stones, boulders, and bedrock that in combination cover more than 75% of the channel. Most common in mountainous areas. |
| Streambed, Cobble/Gravel | At least 25% of the substrate is covered by unconsolidated particles smaller than stones; cobbles or gravel predominate. The subclass occurs in riffle areas or in the channels of braided streams. |
| Streambed, Sand | Sand-sized particles predominate among the particles smaller than stones. Sand Streambed often contains bars and beaches interspersed with mud streambed or it may be interspersed with Cobble-Gravel streambed in areas of fast flow or heavy sediment load. |
| Streambed, Mud | The particles smaller than stones are chiefly silt or clay. Mud Streambeds are common in arid areas where intermittent flow is characteristic of streams of low gradient. Such species as tamarisk (Tamarix gallica) may occur, but are not dense enough to qualify the area for classification as Scrub-Shrub Wetland. |
| Streambed, Organic | Characterized by channels formed in peat or muck. |
| Streambed, Vegetated | These streambeds are exposed long enough to be colonized by herbaceous annuals or seedling herbaceous perennials (pioneer plants). This vegetation, unlike that of Emergent Wetlands, is usually killed by rising water levels or sudden flooding. |
| Scrub/shrub | Occur only in Estuarine and Palustrine systems. The class Scrub-Shrub Wetland includes areas dominated by woody vegetation less than 6 m (20 ft) tall. The species include true shrubs, young trees, and trees or shrubs that are small or stunted because of environmental conditions. All water regimes except subtidal are included. |
| Scrub/shrub, All subclasses | See SS1-7 for information. |
| Scrub/shrub, Broad-leaved deciduous | Palustrine system examples are willows, alders, buttonbush, redosier dogwood, spirea, bog birch, etc. |
| Scrub/shrub, Needle-leaved deciduous | Consisting of wetlands where trees or shrubs are predominantly deciduous and needle-leaved, represented by young or stunted trees such as tamarack or bald cypress. |
| Scrub/shrub, Broad-leaved evergreen | In Palustrine system, the broad-leaved evergreen species are typically found on organic soils. Examples are fetterbush, inkberry and the semi-evergreen black ti-ti. |
| Scrub/shrub, Needle-leaved evergreen | The dominant species are young or stunted trees such as black spruce or pond pine (Pinus serotina). |
| Scrub/shrub, Dead | Dead woody plants less than 6 m tall. These wetlands are usually produced by a prolonged rise in the water table resulting from impoundment of water by landslides, man or beavers. |
| Scrub/shrub, Deciduous | |
| Scrub/shrub, Evergreen | |
| Unconsolidated bottom | Includes all wetland and deepwater habitats with at least 25% cover of particles smaller than stones, and a vegetative cover less than 30%. Water regimes are restricted to subtidal, permanently flooded, intermittently exposed, and semipermanently flooded. Unconsolidated Bottoms are characterized by the lack of large stable surfaces for plant and animal attachment. They are usually found in areas with lower energy than Rock Bottoms, and may be very unstable. |
| Unconsolidated bottom, All subclasses | See UB1-4 for information. |
| Unconsolidated bottom, Cobble/gravel | The unconsolidated particles smaller than stones are predominantly cobble, and gravel, although finer sediments may be intermixed. |
| Unconsolidated bottom, Sand | The unconsolidated particles smaller than stones are predominantly sand, although finer or coarser sedimants may be intermixed. |
| Unconsolidated bottom, Mud | The unconsolidated particles smaller than stones are predominantly silt and clay, although coarser sediments or organic material may be intermixed. Organisms living in mud must be able to adapt to low oxygen concentrations. |
| Unconsolidated bottom, Organic | The unconsolidated material smaller than stones is predominantly organic. The number of species is limited and faunal productivity is very low (Welch 1952). |
| Unconsolidated shore, All subclasses | See US1-5 for information. |
| Unconsolidated shore, Cobble/Gravel | The unconsolidated particles smaller than stones are predominantly cobble and gravel that have been transported away from Cobble-Gravel shores by waves and currents. |
| Unconsolidated shore, Sand | The unconsolidated particles smaller than stones are predominantly sand which may be either calcareous or terrigenous in origin. |
| Unconsolidated shore, Mud | The unconsolidated particles smaller than stones are predominantly silt and clay. |
| Unconsolidated shore, Organic | The unconsolidated particles smaller than stones are predominantly organic soils of formerly vegetated wetlands. |
| Unconsolidated shore, Vegetated | Some nontidal shores are exposed for a sufficient period to be colonized by herbaceous annuals or seedling herbaceous perennials (pioneer plants). |
| Unconsolidated shore | Includes all wetland habitats having three characteristics: 1) unconsolidated substrates with less than 75% areal cover of stones, boulders, or bedrock; 2) less than 30% areal cover of vegetation other than pioneering plants; and 3) any of the following water regimes: irregularly exposed, regularly flooded, irregularly flooded, seasonally flooded, intermittently flooded, saturated, or artificially flooded. Intermittent or intertidal channels of the Riverine system classified are as Streambed. |
