Article Index

Glossary of General Wetland and Watershed Terms


Acid – pH of water less than 5.5; pH modifier used in the U.S. Fish and Wildlife Service wetland classification system

Acidic – has a pH of less than 7

Acre – a measure of land, 43,560 square feet

Acre-Foot (acre–ft.) – the volume of water needed to cover an acre of land to a depth of one foot; equivalent to 43,560 cubic feet or 325,851 gallons

Adaptation – evolutionary process by which an organism becomes better suited to live in a particular environment; how a species changes over time to better live in a particular environment

Adventitious – buds or roots that develop in unusual areas; many wetland plants exhibit adventitious roots
Aerate – to supply air to water, soil, or other media

Areal Cover - a measure of dominance that defines the degree to which aboveground portions of plants (not limited to those rooted in a sample plot) cover the ground surface; it is possible for the total areal cover in a community to exceed 100 percent because (a) most plant communities consist of two or more vegetative strata; (b) areal cover is estimated by vegetative layer; and (c) foliage within a single layer may overlap
Aerobic – (of an organism or tissue) requiring air for life; pertaining to or caused by the presence of oxygen

Aesthetic – of beauty or the study of beauty
Algae – simple plants that are very small and live in water through photosynthesis, algae are the main producers of food and oxygen in water environments

Algal Bloom – the rapid proliferation of passively floating, simple plant life, such as blue–green algae, in and on a body of water

Alkaline – has a pH greater than 7; pH modifier in the U.S. Fish and Wildlife Service wetland classification system; in common usage, a pH of water greater than 7.4

Alluvium, Alluvial Soil – soil composed primarily of eroded material such as sand, silt, or clay, that has been deposited on land or on the bottom of water bodies by rivers and streams overflowing their banks
Alpine Snow Glade – a marshy clearing between slopes above the timberline in mountains

Altered Wetland – area affected by anthropogenic or natural events, such that one or more indicators of relative wetland character is absent, obscured, or provides information no longer representative of original condition
Ambient Monitoring – monitoring within natural systems (e.g., lakes, rivers, estuaries, wetlands) to determine existing conditions

Amphibian – an animal that may begin its life in water, but as an adult is at home in both water and land; frogs, salamanders and caecilians (which are found in the tropics only)

Anadromous Fish – migratory species that are born in freshwater, live mostly in estuaries and ocean water, and return to freshwater to spawn

Anaerobic – living in the absence of air or free oxygen; pertaining to or caused by the absence of oxygen

Annual – a plant whose life cycle is completed in one year or one season

Anoxic – without oxygen

Anthropogenic – having to do with or caused by humans

Aerenchymous Tissue - a type of plant tissue in which cells are unusually large and arranged in a manner that results in air spaces in the plant organ; such tissues are often referred to as spongy and usually provide increased buoyancy
Aquatic –taking place in or being in water; consisting of, relating to, or being in water; living or growing in, on, or near the water; aquatic wetlands are those in which the plants, such as lily pads, grow in or on top of the water, but do not emerge above

Aquaculture – the science of farming organisms that live in water, such as fish, shellfish, and algae

Aquifer – a geological formation, such as fractured bedrock, glacial sands or gravels, which contains water and yields significant quantities of water to springs and wells; also known as ground water

Artificial Drainage – removal of free water from soil by surface mounding, ditches, or subsurface tiles to the extent that water table levels are changed significantly in connection with specific land uses

Artificial Wetland – wetland constructed where one did not exist before Aspect – the predominant compass direction in which a site is sloping downward

Assemblage – an association of interacting populations of organisms in a wetland or other habitat; examples of assemblages used for biological assessments include algae, amphibians, birds, macroinvertebrates (insects, crayfish, clams, snails, etc.), and vascular plants

Assessment – evaluation of the condition of an area
Attribute – a measurable component of a biological system

Atypical situation - as used herein, this term refers to areas in which one or more parameters (vegetation, soil, and/or hydrology) have been sufficiently altered by recent human activities or natural events to preclude the presence of wetland indicators of the parameter


Backwater – a body of water in which the flow is slowed or turned back by an obstruction such as a bridge or dam, an opposing current, or the movement of the tide

Bank – the rising ground that borders a stream, pond or other body of water

Bank storage – the change in the amount of water stored in an aquifer resulting from a change in stage of an adjacent surface–water body

Barrier Bar – an elongate offshore ridge submerged at least at high tide, built up by the action of waves or currents

Barrier Beach – a narrow, elongate sandy ridge rising slightly above the high–tide level and extending generally parallel with the mainland shore, but separated from it by a lagoon

Base Flow – the sustained low flow of a stream, usually resulting from groundwater inflow to the stream channel

Basic – the opposite of acidic; has a pH of greater than 7

Bed – the ground under a river, pond or other body of water

Bed Material – sediment composing the streambed

Bedrock – a general term used for solid rock that underlies soils or other unconsolidated material

Benthic Organism – a form of aquatic life that lives on the bottom or near the bottom of streams, lakes, or oceans

Biennial - an event that occurs at 2-year intervals

Biochemical–Oxygen Demand (BOD) – the amount of oxygen, in milligrams per liter, that is removed from aquatic environments by the life processes of microorganisms

Biochemical Process – a process characterized by, produced by, or involving chemical reactions in living organisms

Biodiversity – the sum of all species of plants and animals. An ecosystem is considered healthy when it supports the most diverse numbers and types of species it is capable of supporting
Biological Assessment (Bioassessment) – using biomonitoring data of samples of living organisms to evaluate the condition or health of a place (e.g., a stream, wetland, or woodlot)

Biological Criteria (Biocriteria) – numerical values or narrative expressions that describe the condition of aquatic, biological assemblages of reference sites of a given aquatic life use designation

Biological Integrity – "...the ability of an aquatic ecosystem to support and maintain a balanced, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitats within a region." (Karr, J. R. and D. R. Dudley. 1981. Ecological perspective on water quality goals. Environmental Management 5:55–68)
Biological Monitoring (Biomonitoring) – sampling the biota of a place (e.g., a stream, a woodlot, or a wetland) repetitively to monitor change over time

Biomass – the amount of living matter, in the form of organisms, present in a particular habitat, usually expressed as weight-per-unit area

Biota – the plants and animals living in a habitat
Blackwater Streams – streams that do not carry sediment, are tannic in nature and flow through peat-based areas

Bog –wetlands characterized by a waterlogged, spongy mat of sphagnum moss, ultimately producing a thickness of acid peat; bogs are highly acid and tend to be nutrient poor; they are typically dominated by sedges, evergreen trees and shrubs

Bottom–Land Forest – low-lying forested wetland found along streams and rivers, usually on alluvial flood plains

Brackish – water that contains some salt, but less than seawater; a mixture of fresh and saltwater typically found in estuarine areas

Brownwater Streams – streams that carry sediment and generally originate from the piedmont or mountains

Buffer Zone – the area of land next to a body of water or wetland, where activities such as construction are restricted in order to protect water or water quality

Buttress– broadened bottom of a tree trunk that helps to stabilize a tree growing in wet soil or water


Calcareous – formed of calcium carbonate or magnesium carbonate by biological deposition or inorganic precipitation in sufficient quantities to effervesce when treated with cold hydrochloric acid

Canopy Layer –the uppermost layer of vegetation in a plant community; in forested areas, mature trees comprise the canopy layer, while the tallest herbaceous species constitute the canopy layer in a marsh

Capillary Fringe – a zone immediately above the water table (zero gauge pressure) in which water is drawn upward from the water table by capillary action

Cfs - cubic feet per second - a measurement of water flow

Channel Scour – erosion by flowing water and sediment on a stream channel; results in removal of mud, silt, and sand on the outside curve of a stream bend and the bed material of a stream channel

Channelization – the straightening and deepening of a stream channel to permit the water to move faster or to drain a wet area for farming

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

Chroma – the relative purity or saturation of a color; intensity of distinctive hue as related to grayness; one of the three variables of color

Cienaga – a marshy area where the ground is wet due to the presence of seepage or springs

Circumneutral – pH of water between 5.5 and 7.4; pH modifier used in the U.S. Fish and Wildlife Service wetland classification system

Clay - a sedimentary material with grains smaller than 0.002 millimeters in diameter

cm – centimeter; one inch equals 2.5 cm

Colonial – a group of plants of the same species, spreading by rhizome or rootstock

Composition (Structure) – the composition of the taxonomic grouping such as fish, algae, or macroinvertebrates relating primarily to the kinds and number of organisms in the group

Community – all the groups of organisms living together in the same area, usually interacting or depending on each other for existence; all the living organisms present in an ecosystem
Comprehensive Wetland Determination – a type of wetland determination that is based on the strongest possible evidence, requiring the collection of quantitative data

Coniferous – any tree or shrub that has cones (pine trees)
Confined River – a river or stream that has banks (typically of bedrock) that do not move rapidly over time and are unlikely to erode

Confining Layer – a body of impermeable or distinctly less permeable material stratigraphically adjacent to one or more aquifers that restricts the movement of water into and out of the aquifers
Conservation – careful preservation and protection of natural resources from loss, harm, or waste, planned management of a natural resource to prevent exploitation, destruction or neglect

Constructed or Created Wetlands – former terrestrial environments that have been designed or engineered to establish the necessary conditions (soils, hydrology, and flora/fauna) for a wetland
Contributing Area – the area in a drainage basin that contributes water to streamflow or recharge to an aquifer

Core Sample – a sample of rock, soil, or other material obtained by driving a hollow tube into the undisturbed medium and withdrawing it with its contained sample

Criteria – standards, rules, or tests on which a judgment or decision may be based

Crustacean – the group of animals having a hard shell and joint body parts; crabs or shrimp

Cypress Dome – small, isolated, circular, depressional, forested wetlands, in which cypress predominates, that have convex silhouettes when viewed from a distance


Dam – a barrier built across a body of water

Decay – to rot; the breakdown of disintegration of matter

Deciduous – plants that lose their leaves once a year, usually in winter

Decomposer – an organism that consumes organic waste, reducing it to simple nutrients that can be used again by living things; decomposers include: moulds, insects, worms, and fungi

Deepwater Habitat – permanently flooded lands lying below the deepwater boundary of wetlands

Degraded – condition of the quality of water that has been made unfit for some specified purpose

Delineation – identification and documentation of the boundary between wetlands and uplands
Delta – the low, nearly flat tract of land at or near the mouth of a river, resulting from the accumulation of sediment supplied by the river in such quantities that it is not removed by tides, waves, or currents

Depressional Wetland – a wetland that lay within a depression in the landscape, generally draining a small surface area
Designated Use – classification designated in water quality standards for each waterbody or segment that defines the optimal purpose for that waterbody (examples are drinking water use and aquatic life use)

Detritus – decaying organic matter found in the top layer of soil or mixed with wetland waters; a food source for many small wetland organisms

Dike – a wall or mound built around a low–lying area to prevent flooding; sometimes called a berm or levee

Direct Runoff – the runoff entering stream channels promptly after rainfall or snowmelt

Discharge – the volume of fluid passing a point per unit of time, commonly expressed in cubic feet per second, million gallons per day, gallons per minute, or seconds per minute per day

Discharge Area (ground water) – area where subsurface water is discharged to the land surface, to surface water, or to the atmosphere

Dissolved Oxygen - oxygen dissolved in water and available to aquatic organisms; one of the most important indicators of the condition of a water body; concentrations below 5 mg/l are stressful and may be lethal to many fish and other species

Dissolved Solids – minerals and organic matter dissolved in water

Disturbance – any change in an ecosystem

Diurnal – of or pertaining to a day; occurring over a 24–hour period

Diversity – a combination of the number of taxa (see taxa richness) and the relative abundance of those taxa; a variety of diversity indexes has been developed to calculate diversity

Dominant species – a plant species that exerts a controlling influence on or defines the character of a community

Dormant – period when a plant is not actively growing, but is still alive (i.e., for most wetland plants in NY in the winter)

Drainage Basin – the land area drained by a river or stream; also known as “watershed”; the area is determined by topography that divides drainages between watersheds

Drained – a condition in which ground or surface water has been reduced or eliminated from an area by artificial means

Dredge – to remove the mud and sediment from a wetland area or waterbody

Drought – a prolonged period of less–than–normal precipitation such that the lack of water causes a serious hydrologic imbalance; a period of very dry weather 


Ecological – refers to the relationship between living things and their environment

Ecological Assessment – an evaluation of the status of a water resource system; can be used to detect degradation and if possible, to identify causes of that degradation
Ecological Integrity – the condition of an unimpaired ecosystem when it is both healthy (that is when it can maintain essential ecological processes such as waste assimilation and micro–climate control) and can support evolutionary and co-evolutionary changes over time

Ecology – the branch of biology that studies the interaction of living organisms with each other and their environment

Economic –having to do with the management of finances or with the production, distribution, and consumption of wealth

Ecoregion – a region defined by similarity of climate, landform, soil, potential natural vegetation, hydrology, and other ecologically relevant variables
Ecosystem – an organic community of plants and animals viewed within its physical environment (habitat); the ecosystem results from the interaction between soil, climate, vegetation and animal life

Emergent Plants – water plants with roots and part of the stem submerged below water level, but the rest of the plant is above water; cattails and bulrushes

Emergent Wetland – a wetland class dominated by emergent plants; include marshes and wet meadows. (abbreviated EM)

Emersed – rising above the surface of water

Endangered Species – any species of plant or animal that is having trouble surviving and reproducing; often caused by loss of habitat, not enough food, or pollution; protected by governments in an effort to keep them from becoming extinct

Enhance (wetland) – to improve existing wetlands to benefit a particular function or value, sometimes at the expense of other functions and values

Environment – the sum of all conditions and influences affecting the life of organisms

Ephemeral Stream – a stream or part of a stream that flows only in direct response to precipitation; it receives little or no water from springs, melting snow, or other sources; its channel is at all times above the water table

Erosion – the process whereby materials of the Earth's crust are loosened, dissolved, or worn away and simultaneously moved from one place to another

Estuaries – the part of the wide lower course of a river where its current is met by ocean tides; an arm of the sea that extends inland to meet the mouth of a river; has somewhat salty water and tidal activity

Estuarine Wetlands – tidal wetlands in low–wave–energy environments where the salinity of the water is greater than 0.5 part per thousand and is variable owing to evaporation and the mixing of seawater and freshwater; tidal wetlands of coastal rivers and embayments, salty tidal marshes, mangrove swamps, and tidal flats

Eutrophication – a natural process, that can be accelerated by human activities, whereby the concentration of nutrients in rivers, estuaries, and other bodies of water increases; over time this can result in anaerobic (lack of oxygen) conditions in the water column; the increase of nutrients stimulates algae "blooms" as the algae decays and dies, the availability of dissolved oxygen is reduced; as a result, creatures living in the water accustomed to aerobic conditions perish

Evaporation – the process by which water is changed to gas or vapor; occurs directly from water surfaces and from the soil

Evapotranspiration – a term that includes water discharged to the atmosphere as a result of evaporation from the soil and surface-water bodies and by plant transpiration

Evergreen – plants that retain their leaves throughout the year

Exoskeleton – the hard outer covering that supports or protects the soft tissue of an organism such as the shells on turtles, snails and lobsters

Exotic Species – plants or animals not native to the area

Extirpated – a local population of a species that no longer exists but populations exist elsewhere


Facultative Plant (FAC) – plants which are equally likely to occur in wetlands or non–wetlands (estimated probability 34 to 66 percent)

Facultative Upland Plant (FACU) – plants which usually occur in non– wetlands but are occasionally found in wetlands (estimated probability 1 to 33 percent)

Facultative Wetland Plant (FACW) – plants which usually occur in wetlands (estimated probability 67 to 99 percent)

Fen – peat-accumulating wetland that generally receives water from surface runoff and (or) seepage from mineral soils in addition to direct precipitation; generally alkaline; or slightly acid

Field Indicator – a characteristic observed in the field that indicates the presence of wetland vegetation, hydric soils, and wetland hydrology as defined by the 1987 COE Wetland Delineation Manual

Fill – the process where low-lying, wet land is filled with materials in an attempt to make it arable or suitable for construction, any material that raises the ground elevation of a wetland or waterbody

Fix – to make more stable; plant roots fix soil making it more resistant to erosion

Floating Plants – water plants with floating leaves; may be free-floating, such as duckweed, or attached to the bottom by a root system as in the case with pond lilies

Flooded - a condition in which the soil surface is temporarily covered with flowing 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

Flood Attenuation – a weakening or reduction in the force or intensity of a flood

Flood Plain – a strip of relatively flat land bordering a stream channel that may be overflowed at times of high water; the amount of land inundated during a flood is relative to the severity of a flood event

Floodplain Wetlands – wetlands that are influenced by and associated with floodplains, where the overflowing water of rivers and streams is the dominant hydrologic input
Fluvial – pertaining to a river or stream

Flyway – a specific air route taken by birds during migration

Food Chain – interrelations of organisms that feed upon each other, transferring energy and nutrients; typically solar energy is processed by plants who are eaten by herbivores which in turn are eaten by carnivores: sun –> grass –> mouse –> owl

Food Web – the combined food chains of a community or ecosystem

Frequently Flooded - a flooding class in which flooding is likely to occur often under normal weather conditions (more than 50-percent chance of flooding in any year or more than 50 times in 100 years)

Forested Wetland – a wetland class where the soil is saturated and often inundated, and woody plants taller than 20 feet form the dominant cover, e.g. red maple, American elm, and tamarack; water tolerant shrubs often form a second layer beneath the forest canopy, with a layer of herbaceous plants growing beneath the shrubs (abbreviated FO)

Freshwater – water without salt in it, like ponds and streams

Friable – descriptive of a rock or mineral that crumbles naturally or is easily broken, pulverized, or reduced to powder
Fringe Wetland – wetland near a large body of water that receives significant and regular two-way flow

Function – refers to how wetlands and riparian areas work – the physical, chemical, and biological processes that occur in these settings, which are a result of their physical and biological structure
Functions – the roles that wetlands serve, which are of value to society or environment

Functional Groups – a means of dividing organisms into groups, often based on their method of feeding (e.g., shredder, scraper, filterer, predator), type of food (e.g., fruit, seeds, nectar, insects), or habits (e.g., burrower, climber, clinger)


Geomorphic – pertaining to the form of the Earth or of its surface features

Geomorphology – the science that treats the general configuration of the Earth's surface; the description of landforms

Gleyed – soil condition resulting from prolonged soil saturation, evidenced by the presence of bluish or greenish colors through the soil or in mottles (spots or streaks) among other colors; occurs under reducing soil conditions resulting from soil saturation, by which iron is reduced predominantly to the ferrous state

Ground Water – in the broadest sense, all subsurface water; more commonly that part of the subsurface water in the saturated zone; a layer of underground water that forms when precipitation soaks into the soil and becomes trapped between the soil above and a rock or clay layer below

Ground Water Discharge – ground water that emerges at the land surface, in the form of springs or seepage areas; ground water can also discharge into rivers (via bank seepage) and sustain flow during the drier months

Groundwater Flow System – the underground pathway by which groundwater moves from areas of recharge to areas of discharge

Groundwater Recharge – the process whereby infiltrating rain, snowmelt or surface water enters and replenishes the groundwater stores

Growing Season – the period of the year when the soil temperature at 19.7 inches below the soil surface is above biological zero; for ease of determination this period can be approximated by the number of frost-free days

Gully Erosion – a form of erosion that can occur on riverbanks which is related to overland drainage down the bank and not to river processes


Habitat – the sum total of all the living and non-living factors that surround and potentially influence an organism; a particular organism's environment

Halophyte – a plant that is adapted to grow in salty soils

Hardpan – a relatively hard, impervious, and usually clayey layer of soil lying at or just below land surface-produced as a result of cementation by precipitation of insoluble minerals

Herbs – succulent, non-woody plants that die down at the end of the growing season

Histic Epipedon – an 8- to 16-in. 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 percent organic matter when no clay is present or a minimum of 30 percent organic matter when 60 percent or greater clay is present

Histosol – soil that has organic materials in more than half of the upper 32 inches or of any thickness overlying bedrock; formed almost exclusively in wetlands (except for folists, which are formed in forests)

Hydraulic Head – the height of the free surface of a body of water above a given point beneath the surface

Hydraulic Gradient – the change of hydraulic head per unit of distance in a given direction

Hydric – relating to, marked by, or requiring considerable moisture

Hydric Soil – a soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions that favor the growth and regeneration of hydrophytic vegetation; field indicators of hydric soils can include: a thick layer of decomposing plant material on the surface; the odor of rotten eggs; and colors of bluish–gray, gray, black, or sometimes gray with contrasting brighter spots of color

Hydrogeomorphic – of or pertaining to a synthesis of the geomorphic setting, the water source and its transport, and hydrodynamics

Hydrogeomorphic (HGM) Classification – a wetland classification system based on the position of a wetland in the landscape (geomorphic setting), dominant sources of water, and the flow and fluctuation of water once in the wetland; hydrogeomorphic classes include riverine, depressional, slope, mineral soil flats, organic soil flats, estuarine fringe, and lacustrine fringe

Hydrogeomorphic (HGM) Approach – a method that compares a wetland's functions (e.g., water retention, nutrient cycling) to similar wetlands of the same type (as defined by HGM classification) that are relatively unaltered; HGM functions normally fall into one of three major categories: (1) hydrologic (e.g., storage of surface water), (2) biogeochemical (e.g., removal of elements and compounds), and (3) habitat (e.g., maintenance of plant and animal communities)

Hydrologic Cycle – the circulation of water from the sea, through the atmosphere, to the land, and thence back to the sea by overland and subterranean routes

Hydrology – the study of the cycle of water movement on, over and through the earth's surface; the science dealing with the properties, distribution, and circulation of water
Hydroperiod – depth, duration, seasonality, and frequency of flooding

Hydrophyte – plants that have adapted mechanisms for survival in saturated or inundated soils with anaerobic conditions; examples include cattails, bulrushes, willows; a plant that can, and often must, live in water


Immersed – covered completely in a liquid; submerged

Impact – a change in the chemical, physical (including habitat), or biological quality or condition of a waterbody caused by external forces
Impaired – condition of the quality of water that has been adversely affected for a specific use by contamination or pollution.

Impairment – a detrimental effect on the biological integrity of a waterbody caused by an impact that prevents attainment of the designated use
Index of Biological Integrity – an integrative expression of site condition across multiple metrics; often composed of at least seven metrics; plural form is either indices or indexes; similar to economic indexes used for expressing the condition of the economy

Indicator – organism, ecological community, or structural feature so strictly associated with a particular environmental condition that its presence indicates the existence of the condition

Infiltration – the downward movement of water from the atmosphere into soil or porous rock

Inorganic – containing no carbon; matter other than plant or animal

Inorganic Soil – soil with less than 20 percent organic matter in the upper 16 inches

Interdependent – mutually dependent

Interface – in hydrology, the contact zone between two fluids of different chemical or physical makeup

Intermittent Stream – streams that flow primarily during the wet seasons when the water table is high, and remain dry for a portion of the year; most intermittent streams flow for a good portion of the year

Intertidal – alternately flooded and exposed by tides

Intertidal Habitat – the tidal area between the mean lower low water and mean higher high water which is alternately exposed and covered by water twice daily

Inundation – a condition in which water from any source temporarily or permanently covers a land surface.

Invertebrate – an animal with no backbone or spinal column; invertebrates include 95% of the animal kingdom

Ion – a positively or negatively charged atom or group of atoms

Irrigation – controlled application of water to arable land to supply requirements of crops not satisfied by rainfall

Isolated Wetland – wetland not regulated by the COE because it does not have an interstate commerce connection; typically does not have surface water connection to other waters or wetlands


Jurisdictional Wetlands – wetlands which are under the jurisdiction of the COE and the EPA pursuant to Section 404 of the federal Clean Water Act because they meet the COE and EPA definition of wetlands; those areas which "...are inundated or saturated by surface or ground water at a frequency and duration to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions"; identified in the field based on the 1987 Corps of Engineers Wetland Delineation Manual which requires indicators of the following three parameters:

A) a dominance of wetland plants;

B) hydric soils; and

C) wetlands hydrology


Karst – a type of topography that results from dissolution and collapse of carbonate rocks such as limestone, dolomite, and gypsum, and that is characterized by closed depressions or sinkholes, caves, and underground drainage

Kettle – a steep-sided hole or depression, commonly without surface drainage, formed by the melting of a large detached block of stagnant ice that had been buried in the glacial drift

Kettle Lake – a body of water occupying a kettle, as in a pitted outwash plain or in a kettle moraine

Knee– A part of the root of a wetland tree that emerges from the water in which the tree is growing; common on bald cypress (see “pneumatophore”)


Lacustrine – pertaining to, produced by, or formed in a lake

Lacustrine Wetlands – wetlands within a lake or reservoir greater than 20 acres or within a lake or reservoir less than 20 acres if the water is greater than 2 meters deep in the deepest part of the basin; ocean-derived salinity must be less than 0.5 part per thousand

Lagoon – a shallow stretch of seawater (or lake water) near or communicating with the sea (or lake) and partly or completely separated from it by a low, narrow, elongate strip of land

Landscape – a heterogeneous mix of properties that encompass more than one ownership or management unit
Landscape Ecology – specialty that deals with the patterns and processes of biological systems at the scale of hundreds to thousands of acres

Landscape Perspective – method of viewing the interactive parts of a geographic areas that are not necessarily in the same watershed

Leachate – a liquid that has percolated through soil containing soluble substances and that contains certain amounts of these substances in solution

Life Zone – major area of plant and animal life; region characterized by particular plants and animals and distinguished by temperature differences

Limnetic – the deepwater zone (greater than 2 meters deep); a subsystem of the Lacustrine System in the U.S. Fish and Wildlife Service wetland classification system

Littoral – the shallow–water zone (less than 2 meters deep) at the edge of a lake or pond; a subsystem in the Lacustrine System of the U.S. Fish and Wildlife Service wetland classification system

Load – material that is moved or carried by streams, reported as weight of material transported during a specified time period, such as tons per year

Lotic – pertaining to or living in flowing water


m – meter; there are approximately 39 inches in a meter

Macroinvertebrates – animals without backbones that can be seen with the naked eye (caught with a 1-mm2 mesh net); includes insects, crayfish, snails, mussels, clams, fairy shrimp, etc.

Macrophyte – any plant species that can be readily observed without the aid of optical magnification; this includes all vascular plant species and mosses (e.g., Sphagnum spp.), as well as large algae (e.g. Chara spp., kelp)

Macrophytic – a term referring to a plant species that is a macrophyte

Main Stem – the principal trunk of a river or a stream

Man-Induced Wetland – any area that develops wetland characteristics due to some activity (e.g., irrigation) of man

Mangroves – tropical evergreen trees found in swamps

Mangrove Forest – wetland in tropical areas, such as the coasts of Florida, Africa, Mexico, Australia, that has mangrove trees and either fresh or salt water

Marine Wetland – wetlands that are exposed to waves and currents of the open ocean and to water having a salinity greater than 30 parts per thousand; present along the coastlines of the open ocean

Marsh – an area of soft, wet, low–lying land, characterized by grassy vegetation and often forming a transition zone between water and land; marshes are dominated by non-woody vegetation and they tend to develop in zones progressing from terrestrial habitat to open water
Maturity – a stage in the evolutionary erosion of land areas where the flat uplands have been widely dissected by deep river valleys

Maturity (stream) – the stage in the development of a stream at which it has reached its maximum efficiency, when velocity is just sufficient to carry the sediment delivered to it by tributaries; characterized by a broad, open, flat–floored valley having a moderate gradient and gentle slope

Mean Low Tide – the average altitude of all low tides recorded at a given place over a 19–year period

Mean High Tide – the average altitude of all high tides recorded at a given place over a 19–year period

Mesophyte – any plant growing where moisture and aeration conditions lie between the extremes of "wet" and "dry"

Method – a particular procedure or set of procedures to be followed

mg/l – milligrams per liter; a unit of concentration

Migratory – a creature that moves from one region to another when the seasons change

Mineral soil – soil composed predominantly of mineral rather than organic materials; less than 20 percent organic material

Mitigation – a process of minimizing or compensating for damages to natural habitats, caused by human developments; these activities are designed to decrease the degree of damage to an ecosystem and may include restoration, enhancement, or creation; according to the Clean Water Act, mitigation is a sequential process that includes avoiding impacts, then minimizing impacts, and lastly, compensating for impacts
Monitoring – the regular measurement of an area or quantity/quality over time (generally of things that can change)

Mottle – contrasting spots of bright colors in a soil; an indication of some oxidation or ground water level fluctuation

Muck – dark, finely divided, well–decomposed, organic matter forming a surface deposit in some poorly drained areas

Mudflat – bare, flat bottoms of lakes, rivers and ponds, or coastal waters, largely filled with organic deposits, freshly exposed by a lowering of the water level; a broad expanse of muddy substrate commonly occurring in estuaries and bays

Muskeg – large expanses of peatlands or bogs that occur in sub arctic zones


Native – an animal or plant that lives or grows naturally in a certain region

Natural Levee – a long, broad, low ridge built by a stream on its flood plain along one or both banks of its channel in time of flood

Naturalist – a person who appreciates, studies and interprets the natural environment

Navigable Water – a water that has in the past, currently is or can be used for interstate commerce (i.e., movement of logs downstate); term is defined differently by the COE under the different regulatory programs

Niche – the way of life of an organism; how it get its food, its behavior and impact on other organisms and habitat; the location and function of a living organism in its environment

Nonpersistent Emergent Plants – emergent plants whose leaves and stems break down at the end of the growing season from decay or by the physical forces of waves and ice; at certain seasons, there are no visible traces of the plants above the surface of the water

Nonpoint Source – a source (of any water–carried material) from a broad area, rather than from discrete points

Nonrenewable – something that is limited in supply and cannot be replenished by natural processes, at least for thousands of years; fossil fuels are a nonrenewable resource

Nuisance Species – undesirable plants and animals, commonly exotic species

Nutrient – any inorganic or organic compound that provides the nourishment needed for the survival of an organism


Obligate Upland Plant (UPL) – plants which almost always occur in uplands (estimated probability greater than 99 percent)

Obligate Wetland Plant (OBL) – plants which almost always occur in wetlands (estimated probability greater than 99 percent)

Off-site Determination Method – a method of assessing, from an office, the probability and estimated size/location of wetlands on a site

Oligotrophic – poor in nutrients; said of lakes and ponds

One–Hundred–Year Flood – refers to the floodwater levels that would occur once in 100 years, or as a 1.0 percent probability per year

On-site Determination Method – a method for identifying the location and extent of wetlands from the field

Open Water – a wetland class consisting of areas of open water less than 6.6 feet deep; there are often submerged or floating–leaved plants in the shallower portions along the edges of the waterbody (abbreviated OW)

Ordinary High Water Mark – that line on the shore established by the fluctuations of water and indicated by physical characteristics such as clear, natural line impressed on the bank, shelving, changes in the character of soil, destruction of terrestrial vegetation, the presence of litter and debris, or other appropriate means that consider the characteristics of the surrounding areas

Organic – containing carbon, but possibly also containing hydrogen, oxygen, chlorine, nitrogen, and other elements

Organic Material – anything that is living or was living; in soil it is usually made up of nuts, leaves, twigs, bark, etc.

Organic Soil – soil that contains more than 20 percent organic matter in the upper 16 inches

Organic Waste – the decaying or decayed matter from once living organisms

Organism – a living thing

Overland Flow – the flow of rainwater or snowmelt over the land surface toward stream channels

Oxbow – a bow–shaped lake formed in an abandoned meander of a river

Oxidized Rhizosphere – precipitation of orange-ish ferric compounds around the roots and rhizomes of plants growing in frequently saturated soils; caused by oxidation of the soil immediately surrounding the root from the discharge of oxygen by the roots or rhizomes of a plant


Palustrine Wetlands – freshwater wetlands including open water bodies of less than 20 acres in which water is less than 2 meters deep; includes marshes, wet meadows, fens, playas, potholes, pocosins, bogs, swamps, and shallow ponds; most wetlands are classified as Palustrine

Parameter– a characteristic component of a unit that can be defined; vegetation, soil, and hydrology are three parameters that may be used to define wetlands

Peat – organic material (leaves, bark, nuts) that has decayed partially; it is dark brown with identifiable plant parts, and can be found in peatlands and bogs

Perched Groundwater – unconfined ground water separated from an underlying main body of ground water by an unsaturated zone, typically by an impermeable clay layer

Percolation – the movement, under hydrostatic pressure, of water through interstices of a rock or soil (except the movement through large openings such as caves)

Perennial – a plant that grows year after year

Perennial Stream – a stream that normally has water in its channel at all times because it is sustained by groundwater discharge as well as by surface runoff

Periphyton – micro–organisms that coat rocks, plants, and other surfaces on lake bottoms

Permeability – the capacity of a rock for transmitting a fluid; a measure of the relative ease with which a porous medium can transmit a liquid

Persistent Emergent Plant – species of plants whose stems show above the water and do not deteriorate when the plant goes dormant (e.g. cattails)

pH – a measure of the acidity (less than 7) or alkalinity (greater than 7) of a solution; a pH of 7 is considered neutral

Physiographic Province – a region in which the landforms differ significantly from those of adjacent regions

Physiography – a description of the surface features of the Earth, with an emphasis on the mode or origin

Photosynthesis – process by which green plants (chlorophyll containing) make food by combining carbon dioxide and water using energy from sunlight

Phytoplankton – microscopic, free–floating plants that drift in the water

Pioneer Plant – herbaceous annual and perennial seedling plants that colonize bare areas as a first stage in secondary succession
Piping – erosion by percolating water in a layer of subsoil, resulting in caving and in the formation of narrow conduits, tunnels, or "pipes" through which soluble or granular soil material is removed

Playa – a dry, flat area at the lowest part of an undrained desert basin in which water accumulates and is quickly evaporated; underlain by stratified clay, silt, or sand and commonly by soluble salts; term used in Southwestern United States

Playa Lake – a shallow, temporary lake in an arid or semiarid region, covering or occupying a playa in the wet season but drying up in summer; temporary lake that upon evaporation leaves or forms a playa
Pneumatophore – specialized roots formed on several species of plants occurring frequently in inundated habitats; root is erect and protrudes above the soil surface

Pocosin – a local term along the Atlantic coastal plain, from Virginia south, for a shrub-scrub wetland located on a relatively flat terrain, often between streams

Point Source – originating at any discrete source (i.e., a discharge pipe)

Pollution – The Clean Water Act (Section 502.19) defines pollution as "the [hu]man-made or [hu]man-induced alteration of chemical, physical, biological, and radiological integrity of water."
Pond – a relatively small body of standing, fresh water; usually shallow enough for sunlight to reach the bed

Ponded – a condition in which water stands in a closed depression; water may be removed only by percolation, evaporation, and/or transpiration

Poorly Drained – water is removed from the soil so slowly that the soil is saturated periodically during the growing season or remains wet for long periods

Population – a collection of individuals of one species or mixed species making up the residents of a prescribed area

Porosity – the ratio of the volume of voids in a rock or soil to the total volume

Positive Wetland Indicator – any evidence of the presence of hydrophytic vegetation, hydric soil, and/or wetland hydrology in an area

Potential Evapotranspiration – the amount of moisture which, if available, would be removed from a given land area by evapotranspiration, expressed in units of water depth

Pothole or Prairie Pothole – a term often used to describe the small, shallow ponds and marshes formed by Pleistocene glaciation in the grasslands of the northern United States and southern Canada; "kettlehole" was the original term used
ppt – parts per thousand. The salinity of ocean water is approximately 35 ppt

Precipitation – the process by which condensed water builds up in clouds and falls to the ground as rain, sleet, snow, or hail

Preservation – the protection and maintenance of organisms or ecosystems for personal or special use

Prevalence Index – weighted average; a single number that summarizes quantitative data about a large number of species within a community and gives weight to each species’ contribution to the final number in terms of an assigned value

Prey – an animal that is eaten by other animals

Prior Converted Wetland – wetland converted to farmable land before December 23, 1985

Pristine – the earliest condition of the quality of a water body; unaffected by human activities

Public Participation – involvement by citizens in the community, especially in decision-making


Quadrat – an area of a certain size (generally from 1 to 20 square meters) within which biodiversity is assessed/ monitored

Quantitative – a precise measurement or determination expressed numerically


Ramsar Convention – an intergovernmental treaty for the conservation of wetlands

Rapid Assessment – an assessment methodology that can be able to be completed in a short time (i.e., a few hours)

Reach – a continuous part of a stream between two specified points

Reaeration – the replenishment of oxygen in water from which oxygen has been removed

Recharge (groundwater) – the process whereby infiltrating rain, snowmelt or surface water enters and replenishes the ground water stores

Recharge Area (groundwater) – an area in which water infiltrates the ground and reaches the zone of saturation

Recurrence Interval – the average interval of time within which the magnitude of a given event, such as a storm or flood, will be equaled or exceeded once

Redox Potential – oxygen-reduction potential; often used to quantify the degree of electrochemical reduction of wetland soils under anoxic conditions

Reference Condition – set of selected measurements or conditions of minimally impaired waterbodies characteristic of a waterbody type in a region

Reference Site – a minimally impaired site that is representative of the expected ecological conditions and integrity of other sites of the same type and region

Regulation (of a stream) – artificial manipulation of the flow of a stream

Renewable – something that can be replaced through natural processes if not overused or contaminated

Reserve – land put aside by the government with the intent to protect a habitat

Resilience – the ability of land to return to a relatively stable and functioning state following a disturbance Resource – something that is available that can be used to take care of a need

Restore – to return a wetland (or other natural habitat) to a close approximation of its condition prior to disturbance by modifying conditions responsible for the loss or change

Return Flow – that part of irrigation water that is not consumed by evapotranspiration and that returns to its source or another body of water

Riparian – pertaining to or situated on the bank of a natural body of flowing water

Riparian Area – an area of streamside vegetation including the stream bank and adjoining floodplain, which is distinguishable from upland areas in terms of vegetation, soils, and topography
Riparian Forest – a swamp that is narrow in width and runs along the shore of and affects a river or stream

Riverine Wetlands – wetlands within river and stream channels; ocean–derived salinity is less than 0.5 part per thousand

Rhizome – an elongated, underground root, which usually grows horizontally and from which may sprout new plants

Rhizosphere– the zone of soil in which interactions between living plant roots and microorganisms occur

Root zone– the portion of a soil profile in which plant roots occur

Routine Wetland Determination– a type of wetland determination in which office data and/or relatively simple, rapidly applied onsite methods are employed to determine whether or not an area is a wetland; most wetland determinations are of this type, which usually does not require collection of quantitative data

Runoff – rainwater that flows over the land and into streams and lakes; it often picks up soil particles along the way and transports it into streams and lakes

Rush – grass–like plant that forms dense clumps, mostly in wet areas; needle-like stems are cylindrical or flattened, hollow and green; “rushes are round, sedges have edges”


Salina – an area where deposits of crystalline salt are formed, such as a salt flat; a body of saline water, such as a saline playa or salt marsh

Saline Water – water that is considered generally unsuitable for human consumption or for irrigation because of its high content of dissolved solids; generally expressed as milligrams per liter (mg/L) of dissolved solids; seawater is generally considered to contain more than 35,000 mg/L of dissolved solids

Salinity – the concentration of dissolved salts in a body of water; commonly expressed as parts per thousand

Sample Plot– an area of land used for measuring or observing existing conditions.

Salt Flat – the level, salt-encrusted bottom of a dried up lake or pond

Salt Marsh – flat land dominated by non-woody vegetation that is flooded by salt water brought in by tides; it is found along saltwater rivers, bays, and oceans

Salt Meadow – a meadow subject to overflow by salt water

Saltwater – water with a high concentration of salt; sometimes used synonymously with seawater or saline water

Sand – a sedimentary material, finer than a granule and coarser than silt, with grains between 0.06 and 2.0 millimeters in diameter

Saturated Zone – generally the zone within sediment and rock formations where all voids are filled with water under pressure greater than atmospheric

Saturation – a condition in which all easily drained voids (pores) between soil particles are temporarily or permanently filled with water; soil has as much water in it as it can hold

SAV – see submerged aquatic vegetation

Scrub – a straggly, stunted tree or shrub; a growth or tract of stunted vegetation

Scrub–Shrub Wetland – a wetland class dominated by shrubs and woody plants that are less than 20 feet tall, e.g. dogwoods, alders, red maple saplings, etc.; water levels in shrub swamps can range from permanent to intermittent flooding (abbr. SS)

Sea Level – the long–term average position of the sea surface; in this volume, it refers to the National Geodetic Vertical Datum of 1929

Secondary Succession – an association of plants that develops after the destruction of all or part of the original plant community

Sediment – fine–grained mineral and organic material in suspension, in transit, or deposited by air, water, or ice on the earth's surface

Sedimentation – the act or process of forming or accumulating sediment in layers; the process of deposition of sediment

Sedge – grass–like plant, usually with solid triangular stems; “rushes are round, sedges have edges”

Seep – a wetland that forms in areas where groundwater discharges to the land surface, often at the base of steep slopes, but where water volume is too small to create a stream or creek; these wetlands have a perpetually saturated soil but may have little or no standing water

Shallows – a term applied to a shallow place or area in a body of water; a shoal

Shrub – a woody plant generally less than 7 meters in height, having several stems arising from the base and lacking a single trunk; a bush

Shrubland – land covered predominantly with shrubs

Shoal – a relatively shallow place in a stream, lake, or sea

Silt – one of three main parts of soil (sand, silt, and clay); silt is small rock particles that are between .05 mm and .002 mm in diameter

Siltation – the deposition or accumulation of silt (or small–grained material) in a body of water

Silviculture – the cultivation of forest trees

Sinkhole – a depression in an area underlain by limestone; its drainage is subterranean

Site – the portion of land chosen as the basis for an activity or ecological assessment

Slough – a swamp or swamp-like region; a marshy or reedy pool, pond, inlet, backwater or the like; a small marshy tract lying in a swale or other local shallow undrained depression; a sluggish creek or channel in a wetland

Slump – a common form of riverbank erosion; can be caused by floodwaters saturating the soil then falling quickly and carrying the bank sediments with them, or by undercutting at the base of the bank causing the section of bank above to topple; usually semi–circular in shape and can vary from a few meters across up to 30m across

Soil– unconsolidated mineral and organic material that supports, or is capable of supporting, plants, and which has recognizable properties due to the integrated effect of climate and living matter acting upon parent material, as conditioned by relief over time

Soil Horizon – a layer of soil that is distinguishable from adjacent layers by characteristic physical and chemical properties

Soil Matrix – the portion of a given soil that has the dominant color; in most cases the portion of the soil that has more than 50% of the same color

Soil Moisture – water occurring in the pore spaces between the soil particles in the unsaturated zone from which water is discharged by the transpiration of plants or by evaporation from the soil

Soil Profile – a vertical section of a soil through all its horizons and extending into the parent material

Soil Types – soils are commonly said to be sandy, loamy or clayey; sandy soils are dominated by sand and fall apart easily and do not have good water retention; loamy soils are where organic matter makes the soil dark and friable, with good moisture retention; clayey soils are dominated by clay to such an extent that you can squeeze a 'ribbon' out of the moist soil

Somewhat Poorly Drained– soils that are wet near enough to the surface or long enough that planting or harvesting operations or crop growth is markedly restricted unless artificial drainage is provided; commonly have a layer with low hydraulic conductivity, wet conditions high in the profile, additions of water through seepage, or a combination of these conditions

Spoil – overburden or other waste material removed in mining, quarrying, dredging, or excavating

Spring – area where there is a concentrated discharge of ground water that flows at the ground surface

Stage – height of the water surface above an established datum plane, such as in a river above a predetermined point that may (or may not) be near the channel floor

Staining – dark brown marks left on trees and on the ground made by water

Stakeholder – any person or organization with an interest in a site, project or issue

Storm Surge – an abnormal and sudden rise of the sea along a shore as a result of the winds of a storm

Stratigraphy – features of geology dealing with the origin, composition, distribution, and succession of geologic strata (layers)

Streamflow – the discharge of water in a natural channel

Submerged Aquatic Vegetation – plants that live entirely under water

Submergent – plants that grow and reproduce while completely submerged by water, e.g. coontail and bladderworts

Submersed Plant – a plant that lies entirely beneath the water surface, except for flowering parts in some species

Subsidence – the gradual downward settling or sinking of the Earth's surface with little or no horizontal motion

Substrate – the base or material on which an organism lives; subsoil

Subtidal – continuously submerged; an area affected by ocean tides

Surface Runoff – water that flows over the surface of the land as a result of rainfall or snowmelt; surface runoff enters streams and rivers to become channelized stream flow

Surface Water – water present above the substrate or soil surface; an open body of water such as a lake, river, or stream

Survey – to examine the condition of an area or quality; to measure, record and map the locations at particular points or boundaries on a site

Suspended Sediment – sediment that is transported in suspension by a stream

Swale – a slight depression, sometimes filled with water, in the midst of generally level land

Swamp – a wetland where the soil is saturated and often inundated and dominated by shrubs (e.g., alder) or trees (e.g., red maple); contrasting with a marsh that has non–woody plants

Systems – a group of interacting, interrelated, or interdependent elements forming a complex whole


Tarn – a relatively small and deep, steep–sided lake or pool occupying an ice–gouged basin amid glaciated mountains

Taxa – a grouping of organisms given a formal taxonomic name such as species, genus, family, etc. (singular form is taxon)

Taxa Richness – the number of distinct species or taxa that are found in an assemblage, community, or sample

Terrestrial – pertaining to, consisting of, or representing the Earth; refers to anything that is land based

Terrain – physical features of a tract of land

Tidal Flat – an extensive, nearly horizontal, tract of land that is alternately covered and uncovered by the tide and consists of unconsolidated sediment

Tidal Prism – the total volume of water passing in and out of a particular area, such as a lagoon or salt marsh, during a tidal cycle

Tidal Wetland – a wetland that is subject to the periodic rising and falling of sea level generated by the gravitational forces of the moon and the sun.

Tide – the rhythmic, alternate rise and fall of the surface (or water level) of the ocean, and connected bodies of water, occurring twice a day over most of the Earth, resulting from the gravitational attraction of the Moon, and to a lesser degree, the Sun

Toe – the base of the riverbank, streambank, or slope

Top Soil – the top layer of soil; it is full of organic material and can be good for growing crops

Topography – the general configuration of a land surface or any part of the Earth's surface, including its relief and the position of its natural and man–made features

Transect – a straight line of certain length marked out through a wetland or upland, along which biodiversity is assessed or monitored

Transitional Habitat – areas where communities shift from one type (i.e. wetland) to another (i.e. upland), where boundaries between the two can be unclear; also used to describe a particular piece of ground that is in transition because of responding to changed conditions, for example an area where vegetation is becoming re–established after having been graded

Transpiration – the process by which water passes through living organisms, primarily plants, into the atmosphere

Trees – woody plants greater than 7 meters tall, and usually with one main trunk

Tundra – a vast, nearly level, treeless plain of the arctic and sub arctic regions. It usually has a marshy surface that supports mosses, lichens, and low shrubs, underlain by mucky soils and permafrost

Turbidity – the state, condition, or quality of opaqueness or reduced clarity of a fluid due to the presence of suspended matter

Turbid – cloudy or opaque water due to the suspension of sediment


Unconfined Aquifer – an aquifer whose upper surface is a water table free to fluctuate under atmospheric pressure

Unconfined River – a river or stream that flows through soft sediments, capable of being eroded; typically these rivers move across a floodplain with time and have a high bank erosion risk

Under Normal Circumstances - as used in the definition of wetlands, this term refers to situations in which the vegetation has not been substantially altered by man's activities

Undercutting – a process of riverbank erosion whereby the base or 'toe' of the riverbank is 'eaten away' as a result of river flow or wave action. It results in the section of bank above becoming unstable and prone to collapse

Understory – a foliage layer lying beneath and shaded by the main canopy of a forest often formed by shrub vegetation

Unsaturated Zone – a subsurface zone above the water table where the pore spaces may contain a combination of air and water

Upland – a general term for nonwetland; elevated land above low areas along streams or between hills; any elevated region from which rivers gather drainage


Values – the goods and services that come from a biological system, including wetlands and riparian areas, that benefit humans or human society
Vascular Plant – a plant composed of or provided with vessels or ducts that convey water or sap; a fern is an example of this type of plant

Vegetation Structure – the structure of the vegetation in terms of layers, heights and spacing between trees

Vernal Pond – temporary ponds that fill with water in the spring as a result of snowmelt, spring rains, and/or elevated ground water tables and dry up later in the year

Vernal Pool – a small lake or pond that is filled with water for only a short time during the spring; many species of reptiles, amphibians, insects and invertebrates rely on vernal pools for breeding

Very Poorly Drained – water is removed from the soil so slowly that water remains at or on the surface during most of the growing season

Vulnerable – a species that is at risk because of low or declining numbers


Water Budget – an accounting of the inflow to, outflow from, and storage changes of water in a hydrologic unit

Water Column – an imaginary column extending through a water body from its floor to its surface

Water Cycle – the process by which water evaporates into water vapor, condenses into liquid form in the clouds, and precipitates as rain or snow back to Earth

Water Gap – a deep, narrow pass in a mountain ridge, through which a stream flows

Watermark– a line on a tree or other upright structure that represents the maximum static water level reached during an inundation event

Water Quality Standard – a legally established state regulation consisting of three parts: (1) designated uses, (2) criteria, and (3) antidegradation policy

Water Table – the upper level of the portion of the ground (rock) in which all spaces are wholly saturated with water; the water table may be located at or near the land surface or at a depth below the land surface and usually fluctuates from season to season; springs, seepages, marshes or lakes may occur where the water table intersects the land surface

Water Vapor – tiny drops of water floating in the air

Watershed – all the water from precipitation (snow, rain, etc.) that drains into a particular body of water (stream, pond, river, bay, etc.); surface drainage area that contributes water to a lake, river, or other body of water; the area drained by a watercourse; different watersheds are separated by divides or water partings

Wet Meadow – emergent wetlands that are generally seasonally flooded and have saturated soil for much of the growing season. Wet meadows are dominated by grasses, sedges and rushes and are very often cultivated or pastured
Wet Prairie – herbaceous wetland dominated by grasses rather than sedges and with waterlogged soil near the surface but without standing water for most of the year

Wetland – a vegetated ecosystem where water is a dominant factor in its development and existence

Wetlands (Cowardin et al.) – are lands transitional between terrestrial and aquatic systems where the water table is usually at or near the surface or the land is covered by shallow water. For purposes of this classification wetlands must have one or more of the following three attributes: (1) at least periodically, the land supports predominantly hydrophytes (2) the substrate is predominantly undrained hydric soil and (3) the substrate is nonsoil and is saturated with water or covered by shallow water at some time during the growing season of each year. Wetland Boundary– the point on the ground at which a shift from wetlands to nonwetlands or aquatic habitats occurs; these boundaries usually follow contours

Wetland Determination– the process or procedure by which an area is adjudged a wetland or nonwetland

Wetland Function – a process or series of processes that take place within a wetland that are beneficial to the wetland itself, the surrounding ecosystems, and people

Wetland Control Length – the length (feet) of the crest of the restrictive feature that would be overtopped if the water level in the wetland was raised by one foot

Wetland Soil– a soil that has characteristics developed in a reducing atmosphere, which exists when periods of prolonged soil saturation result in anaerobic conditions; hydric soils that are sufficiently wet to support hydrophytic vegetation are wetland soils

Wetland vegetation– the sum total of macrophytic plant life that occurs in areas where the frequency and duration of inundation or soil saturation produce permanently or periodically saturated soils of sufficient duration to exert a controlling influence on the plant species present; hydrophytic vegetation occurring in areas that also have hydric soils and wetland hydrology may be properly referred to as wetland vegetation

Willow Carr – a pool, or wetland dominated by willow trees or shrubs


Zonation – state or condition of being marked with bands, as of color or texture; wetland vegetation often exhibits distinct zones characterized by plant communities composed of different species

Zooplankton – free-floating animals that drift in the water, range from microscopic organisms to larger animals such as jellyfish