Facultative Species - Plant species that can occur both in wetlands and uplands. There are three subcategories of facultative species:

 

Facultative wetland plants,

 

Facultative plants, and

 

Facultative upland plants.

 

Facultative Plants (FAC) - A plant species that is equally likely to occur in wetlands or non-wetlands (estimated probability 34-66%).

 

Facultative Upland Plants (FACU) - A plant species that usually occurs in non-wetlands (estimated probability 67 - 99%), but occasionally is found in wetlands (estimated probability 1 - 33%).

 

Facultative Wetland Plants (FACW) - A plant species that usually occurs in wetlands (estimated probability 67 - 99%), but occasionally is found in non-wetlands.

 

Fen - A non-acidic peat-forming wetland that receives nutrients from sources other than precipitation, usually through groundwater movement.

 

Fibric Materials - Plant materials that show very little signs of decomposition. Plant fiber content before rubbing between fingers is at least 3/4 of the soil volume.

 

Fibrists - Organic soils (peats) in which plant remains show very little decomposition and retain original shape; more than 2/3 of the fibers remain after rubbing the materials between the fingers.

 

Filter Strips - Belts of vegetation (grass, shrubs, and/or trees) maintained along streams or on the contours insloping fields to trap sediment and agricultural chemicals before they enter waterways.

 

Flood Control - Act or technique of trying to control rivers with dams to minimize occurrence of floods. The specific regulations and practices that reduce or prevent the damage caused by stormwater runoff.

 

Flooded - A condition in which the soil surface is temporarily covered with flowing water from any source, such as streams overflowing their banks and runoff from adjacent or surrounding slopes, or any combination of sources.

 

Floodplain - An alluvial plain caused by the overbank deposition of alluvial material. Typically appearing as flat expanses of land bordering a stream or river. Most floodplains are accompanied by a series of alluvial terraces of varying levels. The low-lying land adjoining a river that is sometimes flooded; generally covered by fine-grained sediments (silt and clay) deposited by the river at flood stage.

 

Flowpath - An underground route for groundwater movement, extending from a recharge (intake) zone to a discharge (output) zone such as a shallow stream

 

Fluvial - Pertaining to or produced by the action of moving water.

 

Flux - The amount of flow per unit time (i.e. energy flux or radiation flux). The rate of flow of any quantity, usually a form of energy, through a unit area of specified surface.

 

Forb - A herbaceous plant, usually broadleaved, that is not a graminoid.

 

Forebay - An extra storage space provided near an inlet of a BMP to trap incoming sediments before they accumulate in a pond BMP.

 

Forested Wetland  - A class of wetland habitat characterized by woody vegetation that is 6m (20 ft) tall or taller.

 

Forested Wetlands - Occur near springs and seeps and in areas with naturally high water tables, such as river floodplains. Two general types of forested wetlands occur:

 

Those dominated by coniferous tree species, and

 

Those dominated by deciduous angiosperm tree species.

 

Frequently Flooded - A class of flood frequency in which flooding is common during most years (more than a 50% chance of flooding in any year, or more than 50 times in 100 years).

 

 

Gabion - Wire basket, filled with stones, used to stabilize banks of a water course and to enhance habitat.

 

Gallery Forest - A strip of forest confined to a stream margin or floodplain in an otherwise unforested landscape.

 

Geographic Information Systems  - A computer system for capturing, storing, querying, analyzing, and displaying geographically referenced data.

 

Gleization - A process in saturated or nearly saturated soils which involves the reduction of iron. This process tends to give gray colors (low chroma) to those parts of the soil from which the iron has been reduced or removed and rust colors (high chroma) to those where the iron has oxidized and accumulated.

 

Gleyed Soil (obsolete) - A soil condition resulting from prolonged soil saturation, which is manifested by the presence of bluish or greenish colors through the soil mass or in mottles (spots or streaks) among other colors. Gleying occurs under reducing soil conditions resulting from soil saturation, by which iron is reduced predominantly to the ferrous state. See also redox depletions.

 

Graminoid - Grass or grass-like plant, such as species of the Poaceae (grasses), Cyperaceae (sedges) and Juncaceae (rushes).

 

Greenway  - Undeveloped land usually in cities, set aside or used for recreation or conservation.

 

Ground Water - Water occupying the interconnected pore spaces in the soil or geologic material below the water table, this water has a positive pressure. Water stored under the surface of the earth. It comes in the vast majority of cases from precipitation that falls on the earth's surface. Some of the precipitation washes away immediately into lakes, rivers, and other water reservoirs, but most of the precipitation sinks into the soil, where it may become groundwater.

 

Groundwater Contamination - The pollution of springs and wells from their sources underground. It can result from indiscriminate land disposal of potentially hazardous waste materials that are then dissolved or suspended in free liquids, usually water, and leach downward through the unsaturated profile to the zone of saturation or from improperly constructed or operated wells.

 

Groundwater Recharge - Inflow of water to a groundwater reservoir from the surface. Infiltration of precipitation and its movement to the water table is one form of natural recharge. Also, the volume of water added by this process.

 

Growing Season -  The period from the average date of the last frost (in the United States, this occurs in the spring) to the first frost in the fall ; the following growing season months are assumed for each of the soil temperature regimes:

 

Thermic (February - October)

 

Mesic (March - October)

 

Frigid (May - September)

 

Cryic (June - August)

 

Pergelic (July - August)

 

 

Habitat - The environment in which a plant or animal grows or lives; the surroundings include physical factors such as temperature, moisture, and light, together with biological factors such as the presence of food and predators.

 

Habitat Type - The land areas that supports, or has the potential of supporting, the same primary climax vegetation. A habitat type classification is a vegetation based ecological site classification. It is based on the potential of the site to produce a specific plant community (plant association). It has been used to classify grasslands, shrublands, woodlands, and forests throughout the western United States.

 

Headwaters - The source or upper reaches of a stream; also the upper reaches of a reservoir.

 

Herbaceous – Non-woody vegetation, such as graminoids and forbs. With the characteristics of a herb; describes a plant with no persistent woody stem above ground.

 

Herbicides - A group of chemicals used to kill or reduce the growth of vegetation that is considered undesirable.

 

Hillslope (Hillside) - A part of a hill between its crest and the drainage line at the foot of the hill.

 

Hillslope Hydrology - The hydrologic process taking place on hillslopes. Intrinsically related to stream flow generation.

 

Hillslope Runoff - Precipitation that flows off hillsides and appears in surface streams.

 

Histic Epipedon - A 20 to 40 cm (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% organic matter when no clay is present or a minimum of 30% of organic matter when 60% or more clay is present. Generally, a thin horizon of peat or muck is present if the soil has not been plowed.

 

Histosols - A soil order composed of organic soils (peats and mucks) with generally greater than 50% organic matter in the upper 80 cm (32 in) or that are of any thickness if overlying rock.

 

Horizon - A distinct layer of soil, more or less parallel with soil surface, having similar properties such as color, texture, and permeability; the soil profiles is subdivided into the following major horizons:

 

A horizon - A surface horizon characterized by an accumulation of organic material

 

E horizon - Most commonly a surface horizon, characterized by leaching of organic matter, iron, and clay

 

B horizon - A subsurface horizon characterized by relative accumulation of organic matter, iron, clay, or aluminum

 

C horizon - Undisturbed, unaltered parent material

 

Hydraulic Conductivity - The ability of the soil to transmit water. Also commonly known as the permeability. Darcy found that to relate the flow rate to the hydraulic head and area of flow required a constant of proportionality (termed k) as the hydraulic conductivity. It has units of velocity. Note that the value is a function of both the porous media and the fluid.

 

Hydraulic Gradient - The rate of change in which the head (or energy) is lost as water flows through porous materials. Defined in algebraic form as: i= (h1-h2)/L where h1: head at location 1 (cm), h2: head at location 2 (cm), and L: length of sand column (cm). The change in hydraulic head between two points (e.g., the difference in water level between two points divided by the distance between the two points). In an aquifer, the rate of change of total head per unit of distance of flow at a given point and in a given direction. In a stream, the slope of the hydraulic grade line.

 

Hydraulic Head - The height of the free surface of a body of water above a given subsurface point. The water level at a point upstream from a given point downstream.  The elevation of the hydraulic grade line at a given point of a pressure pipe

 

Hydraulic Radius - Ratio of the cross-sectional area of the flow at a point in an open channel or closed conduit to the wetted perimeter (R = A/P).

 

Hydric Soil - A soil that is saturated, flooded, or ponded long enough during the growing season to develop anaerobic conditions in the upper part of the soil profile. Hydric soil indicators are Histosol, histic epipedon, sulfidic odor, aquic moisture regime, reducing conditions, gleyed or low-chroma colors, concretions, high organic content in surface layer in sandy soils, organic streaking in sandy soils, listed on local Hydric Soils List, and listed on National Hydric Soils List (Environmental Laboratory, 1987).

 

Hydrograph - A graphical representation or plot of changes in the flow of water or changes in the elevation of water level plotted against time.

 

Hydrologic Cycle - The hydrologic cycle begins with precipitation that lands on the earth's surface and can be in the form of rain, snow, etc. From there, the water may spread along the ground surface as surface water runoff or overland flow or may seep into the ground and become ground water. Overland flow may continue to concentrate as channel flow, and progressing as stream flow, continuing to concentrate in the form of streams and rivers until ultimately reaching the ocean. Infiltration causes surface water to change into groundwater.

 

 

Hydrologic Soil Group - SCS classification system of soils based on the permeability and infiltration rates of the soils. "A" type soils are primarily sandy in nature with a high permeability while "D" type soils are primarily clayey in nature with a low permeability. Other groups include "B" and "C" types."

 

Hydrology - The science dealing with the properties, distribution, and circulation of water.

 

Hydrophyte - Any macrophytic plant that grows in water or on a substrate that is at least potentially deficient in oxygen as a result of excessive water content; plants typically found in wetland and other aquatic habitats.

 

Hydrophytic Vegetation - Plant life growing in water or on a substrate that is at least potentially deficient in oxygen as a result of excessive water content.

 

Hyporheic Zone - The volume of sediment and porous space adjacent to a stream, and through which stream water exchanges.

 

 

Impervious Surface  - A hard surface area that either prevents or retards the entry of water into the soil mantle as under natural conditions prior to development. A hard surface area that causes water to run off the surface in greater quantities or at an increased rate of flow from the flow present under natural conditions prior to development. Common impervious surfaces include, but are not limited to, rooftops, walkways, patios, driveways, parking lots, storage areas, concrete or asphalt paving, gravel roads, packed earthen materials, and oiled, macadam, or other surfaces that similarly impede the natural infiltration of urban runoff. Open, uncovered retention/detention facilities shall not be considered as impervious surfaces.

 

Inceptisols - A soil order composed of soils of intermediate development; morphological characteristics are generally too weak to meet requirements of other soil orders.

 

Incidental Type - Refers to a habitat type or community type that rarely occurs or occupies only a small area of a wetland zone.

 

Incision - A depression scratched or carved into a surface.

 

Infiltration - The process by which water enters the soil and that is controlled by the character of the soil and surface conditions, such as slope and amount of vegetation.

 

Intermittent - A stream that flows only periodically throughout the year.

 

Intermittent Stream - A stream or reach of stream which flows only at certain times of the year when it receives water from springs or from some surface source (e.g., melting snow). They are usually divided with respect to the source of their water into spring-fed or surface-fed intermittent streams. These streams generally flow continuously during periods of at least one month or more during the year.

 

Intertidal - Coastal land that is covered by water at high tide and uncovered at low tide.

 

Inundation - A condition in which water temporarily or permanently covers a land surface.

 

Invasive Species - A plant or animal that moves in and takes over an ecosystem to the detriment of other species; often the result of environmental manipulation.

 

Irrigation Canal - Includes all types of canals associated with irrigation systems.

 

 

Lacustrine System - Any wetland or deepwater habitat with the following characteristics:

 

Situated in a topographic depression or dammed river channel,

 

Lacking trees, shrubs, persistent emergents, emergent mosses or lichens with greater than 30% areal coverage, and

 

Total area exceed 8 ha (20 acres).

 

Lake - A natural topographic depression collecting a body of water covering at least 8 ha (20 acres) with surface water.

 

Land Cover - A (bio)physical description of the earth's surface. It is that which overlays or currently covers the ground. This description enables various biophysical categories to be distinguished - basically, areas of vegetation (trees, bushes, fields, lawns), bare soil, hard surfaces (rocks, buildings) and wet areas and bodies of water (watercourses, wetlands). The process of managing the use and development of land resources. Land resources are used for a variety of purposes which interact and may compete with one another; therefore, it is desirable to plan and manage all uses in an integrated manner. Operations for preparing and controlling the implementation of plans for organizing human activities on land. The way land is developed and used in terms of the types of activities allowed (agriculture, residences, industries, etc.) and the size of buildings and structures permitted. Certain types of pollution problems are often associated with particular land uses, such as sedimentation from construction activities. The traits, patterns, and structure of a specific geographic area, including its biological composition, its physical environment, and its anthropogenic or social patterns. An area where interacting ecosystems are grouped and repeated in similar form.

 

Land-Use Planning - A generic term for a wide range of legislative and regulatory activities intended to limit or direct land development for the purpose of making its usage sustainable. Large-scale land-use plans often are implemented by local zoning and land-use ordinances.

 

Leachate - Liquid that has moved through a substance, removing solids from the substance, generally by dissolution.

 

Leaching  - Downward movement of a soluble material through the soil as a result of water movement. The process by which soluble constituents are dissolved and filtered through the soil by a percolating fluid.

 

Lentic Wetland - See still water wetland.

 

Loading - Amount of a substance entering the environment (soil, water, or air).

 

Long Duration (Flooding) - A duration class in which inundation for a single event ranges from 7 days to 1 month.

 

Lotic Wetland - See riparian wetland.

 

 

Macroinvertebrate - Any non-vertebrate organism that is large enough to be seen without the aid of a microscope.

 

Major Type - Refers to a habitat type or community type that occupies an extensive area within a wetland zone.

 

Manning's Roughness Coefficient  - Indicative of the resistance to the flow. Used in formula to compute the velocity of uniform flow in a open channel: V= 1.486/ n R(2/3) S (1/2), where V is the mean velocity of flow (in cfs units), R is the hydraulic radius in feet, S is the slope of the channel or sine of the slope angle, and n is the Manning roughness coefficient.

 

Marsh - A frequently or continually inundated wetland, often developing in shallow ponds, depressions, and river margins. Marshes are dominated by herbaceous plants, such as grasses (e.g., Phragmites), sedges, cattails (e.g., Typha), and bulrushes (e.g., Scirpus). Waters are usually neutral to basic. A type of wetland that does not accumulate appreciable peat deposits and is dominated by herbaceous vegetation. Marshes may be either fresh or saltwater, tidal or non-tidal.

 

Microorganism - A microscopic organism. The term encompasses viruses, bacteria, yeast, molds, protozoa, and small algae.

 

Mineral Soil - Soils composed of predominantly mineral materials (sands, silts, and clays) instead of organic materials. The soil contains less than 20% organic matter.

 

Minor Type - Refers to a habitat type or community type that seldom occupies large areas but may be common within a wetland zone.

 

Mitigation - Actions designed to lessen or reduce adverse impacts. Frequently used in the context of environmental assessment.

 

Mollic Epipedon - A surface layer that consists of mineral soil materials and have the following properties:

 

Soil structure that is not both massive and hard or very hard when dry,

 

Munsell color value less than 3 moist and 5 dry, and chroma less than 3,

 

Base saturation of at least 50%,

 

At least 1% organic matter throughout the horizon,

 

Typically moist for at least 3 months in most years, and

 

At least 18 cm (7 in) thick.

 

Mollisols - A solid order including soils with a thick dark brown to black surface horizon (mollic epipedon), has a high base saturation, and a well-developed structure. Typically associated with grassland soils.

 

Monotypic Stands - Stands composed primarily of a single species.

 

Montane - That region between the subalpine zone and the grassland zone or more broadly, mountain slopes below the alpine zone.

 

Mottling (obsolete) - Spots or blotches of different color or shades of color interspersed with the dominant color in a soil layer, usually resulting from the presence of periodic reducing soil conditions. See also redox concentrations.

 

 

Native - Endemic, i.e. confound to certain area, or originated where it was located.

 

Native Vegetation - Endemic vegetation.

 

Natric Horizon - A special kind of argillic horizon. Natric horizons have all the properties of argillic horizons but, in addition, are 15% or more sodium saturated. Their formation is favored where leaching results in the accumulation of sodium on the cation-exchanger complex.

 

Nitrogen (N)  - An element essential to the growth and development of plants. Occurs in manure and chemical fertilizer and, in excess, can cause waters to become polluted by promoting excessive growth of algae and other aquatic plants.

 

Non-Point Source Pollution  - In general, sources of pollutants entering lakes, rivers, oceans, and other waterways can be classified as point or nonpoint sources. A nonpoint source is a extended area from which water flows, usually on an irregular basis. Examples of nonpoint sources include agricultural land, developed land, forests, or landfills.

 

Nonhydric Soils - A soil that has developed under predominantly unsaturated soil conditions.

 

Nonpersistent Vegetation - Plants that break down readily after the growing season; no evidence of previous year's growth at the beginning of the next growing season.

 

Nonwetland - Any area that has sufficiently dry conditions that hydrophytic vegetation, hydric soils, and/or wetland hydrology are lacking; it includes upland as well as former wetlands that are effectively drained.

 

Nutrient Balance  - The difference between nutrient inputs and outputs. When the nutrient balance is close to zero, nutrients applied in manure and fertilizer are closely matched to crop utilization. When the nutrient balance is positive, nutrient inputs exceed outputs. When the nutrient balance is negative, nutrient outputs exceed inputs.

 

Nutrient Cycle - Pathway of a nutrient through an ecosystem from assimilation (transformation into living tissue) by organisms to release by decomposition. The cyclic conversions of nutrients from one form to another within the biological communities.

 

Nutrient Loading  - Quantity of nutrients entering an ecosystem in a given period of time. The nutrient load refers to the total amount of nitrogen or phosphorus entering the water during a given time, such as "tons of nitrogen per year".

 

Nutrients  - A group of chemical elements or compounds needed for all plant and animal life. Nitrogen and phosphorus are primary nutrients in aquatic systems. Excessive or imbalanced nutrients in water may cause problems such as accelerated eutrophication.

 

 

Obligate Wetland Plant - Refers to a plant species that occurs almost always (estimated probability greater than 99 percent) under natural conditions in wetlands.

 

Ordinance - A law or rule enacted by an authority, such as a city government.

 

Organic Soil - Soils composed of primarily organic rather than mineral material. Equivalent to histosols and includes peats and mucks.

 

Overbank Flooding - Any situation in which inundation occurs as a result of the water level of a river or stream rising above bank level.

 

Overflow Channel - An abandoned channel in a floodplain that may carry water during periods of high stream or river flows.

 

Overland Flow - The flow of water over a land surface due to direct precipitation. Generally occurs when the precipitation rate exceeds the infiltration capacity of the soil.

 

Oxbow Lake - A meander channel of a stream or river that is formed by breaching of a meander loop during flood stage. The ends of the cut-off meander are blocked by bank sediments.

 

 

Palustrine System  - Any nontidal wetland of a class dominated by trees, shrubs, persistent emergents, or emergent mosses or lichens.

 

Parent Material - The unconsolidated and undeveloped mineral or organic matter from which the solum (soil) is developed.

 

Peraquic Moisture Regime - A soil condition in which reducing conditions always occur due to the presence of ground water at or near the soil surface.

 

Percolation - The migration of water through the active soil profile into greater depths where it may become groundwater.

 

Percolation Rate - The rate, usually expressed as a velocity, at which water moves through saturated granular material. Also applies to quantity per unit of time of such movement.

 

Perennial Stream - A stream or reach of a stream that flows continuously. They are generally fed in part by springs. Surface water elevations are commonly lower than water table elevations in adjacent soils. A stream that flows throughout the year. During low-flow periods, the flow of perennial streams is baseflow. Perennial streams are typical of humid and subhumid climates, where groundwater reservoirs are subject to substantial wet-season recharge, discharging during dry season.

 

Perennial Yield  - The maximum quantity of water that can be withdrawn annually from a ground water supply under a given set of conditions without causing an undesirable result.

 

Permanently Flooded - A water regime condition where standing water covers the land surface throughout the year (but may be absent during extreme droughts).

 

Permeability - The quality of the soil that enables water to move downward through the profile, measured as the number of cm (in) per hour that water moves downward through the saturated soil.

 

Pesticides - A broad group of chemicals that kills or controls plants (herbicides), fungus (fungicides), insects and arachnids (insecticides), rodents (rodenticides), bacteria (bactericides), or other creatures that are considered pests.

 

Phase - A subdivision of a habitat type or representing a characteristic variation in climax vegetation and environmental conditions.

 

Phosphorous (P)  - An element essential to the growth and development of plants. Occurs in manure and chemical fertilizer and, in excess, can cause waters to become polluted by promoting excessive growth of algae and other aquatic plants.

 

Photic Zone - The upper water layers from the water surface and extending down to the depth of effective light penetration where photosynthesis balances respiration. This level (the compensation level) usually occurs at the depth of 1 percent light penetration (for example, 1 percent of surface light intensity) and forms the lower boundary of the zone of net metabolic production.

 

Photosynthesis - The process by which plants manufacture food from sunlight. Specifically, the conversion of water and carbon dioxide to complex sugars in plant tissues by the action of chlorophyll driven by solar energy.

 

Phreatophyte - A plant that habitually obtains its water supply from saturated zone, either directly or through the capillary fringe.

 

Pioneer Species - Species that colonize bare areas (e.g., gravel bars) where there is little or no competition from other species.

 

Plant Association - Used to group together all those stands of climax vegetation which occur in environments so similar that there is much floristic similarity throughout all layers of the vegetation.

 

Plant Uptake - The uptake of a chemical into plants is expressed in terms of a bioconcentration factor for vegetation, which is the ratio of the concentration in the plant tissue to the concentration in soil.

 

Playa - A periodically flooded wetland basin. Playas are common in parts of southwest Montana.

 

Plot  - A chart or map showing the movements or progress of an object.

 

Point Source Pollution - In general, sources of pollutants entering lakes, rivers, oceans, and other waterways can be classified as point or nonpoint sources. Point sources are municipal or industrial sites that can be specifically identified as the source from which pollutants are released into a waterway. Such sources might include pipes or canals that flow from a municipal sewage system or industrial plant into a waterway.

 

Pollutant - A contaminant in a concentration or amount that adversely alters the physical, chemical, or biological properties of the natural environment.

 

Pollutant Load - The amount of pollutants entering a water body. Loads are usually expressed in terms of a weight and a time frame, such as pounds per day (lb/d).

 

Pond. Bodies of water encircled by wetland vegetation. Wave action is minimal, allowing emergent vegetation to establish.

 

Ponded. A condition in which free water covers the soil surface, for example, in a closed depression. The water is removed only by percolation, evaporated, or transpiration.

 

Pooled Channel Stream - An intermittent stream with significant surface pool area and without flowing surface water. The water sources for the pools are springs within the channel.

 

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 (greater than 7 days).

 

Population Density - The number per unit area of individuals of any given species, including humans, at a given time.

 

Pothole - A depressional wetland community caused by glaciation and is common to portions of the Northern Great Plains. The body of water is less than 8 ha (20 acres) in size.

 

Precipitation - Forms in which liquid or solid water fall to the earth from the atmosphere. The most common forms of precipitation are rain, sleet, glaze, snow, mist, drizzle, hail, rime, and graupel. Dew and white frost are sometimes considered forms of precipitation.

 

Primary Succession - Occurs on a bare surface not previously occupied by plants, such as a recently deposited alluvial bar.

 

 

Range of Canopy Cover - Refers to the "range" (e.g., low and high values) of canopy cover of a particular species for all the stands sampled for a habitat type or community type.

 

Rational Method - Means of computing peak storm drainage flow rates based on average percent imperviousness of the site, mean rainfall intensity, and drainage area. In hydraulics, the expression of peak discharge (in cfs units) as equal to rainfall (in inches/hr) times drainage area (in acres) times a runoff coefficient depending on drainage basin characteristics. The Rational Method has served as the basis for United States storm drain design practice since the turn of the 20th century. It is essentially a peak discharge method based on the following formula: Q = kCiA ; where Q is the peak flow rate in m3/s for return interval T years, C is the runoff coefficient dependent on land use, i is the design rainfall intensity in cm per hour for return period of T years and duration equal to the time of concentration for the basin, A is the drainage area in hectares, and k =0.0278, the number of m3/s in one hectare-cm/hour.

 

Reach - A segment of a stream channel.

 

Receding Limb - That portion of a hydrograph that shows the rate of decrease of stage or discharge following passage of a crest; the opposite of rising limb.

 

Redox Concentrations - A redoximorphic feature characterized by zones in the soil of apparent accumulation of iron and manganese oxides. These may form as nodules, concretions, soft bodies, or pore linings and vary in shape, size, and color.

 

Redox Depletions - A redoximorphic feature characterized by zones in the soil of low chroma (less than 3) where iron and manganese oxides alone have been removed, or where both iron/manganese oxides and clay have been removed.

 

Redoximorphic Features - Soil features associated with wetness and are formed as a result of the reduction and oxidation of iron and manganese compounds in the soil following saturation with water (See redox concentrations and redox depletions.)

 

Reduced Matrix - A redoximorphic feature characterized by a soil matrix having low chroma (less than 3) in situ, but increases in hue or chroma when exposed (within 30 minutes) to air.

 

Regulated Flow - Flow is regulated when it is managed to achieve various goals, such as maintaining a minimum flow downstream of a reservoir or maintaining a minimum depth for shipping.

 

Reservoir - An artificial (dammed) water body with at least 8 ha (20 acres) covered by surface water.

 

Residence Time  - The average time an element spends in a given environment between the time it arrived and the time it is removed by some process. In the ocean, residence time is defined as the concentration in sea water relative to the amount delivered to the ocean per year; in groundwater, it is the time elapsed between water being recharged to the aquifer; in lakes and reservoirs, it is the time elapsed between a parcel of water entering the waterbody and leaving it.

 

Riparian - adj. Of, on, or relating to the banks of a natural course of water (Latin riparius, from ripa, bank). The bank of a river or stream, or the shoreline of a lake or pond.

 

Riparian Buffer - Vegetated areas next to water resources that protect water resources from nonpoint source pollution and provide bank stabilization and aquatic and wildlife habitat.

 

Riparian Rights  - A concept of water law under which authorization to use water in a stream is based on ownership of the land adjacent to the stream.

 

Riparian Plant Association - A plant community representing the latest successional stage attainable on a specific, hydrologically influenced surface (equivalent potential natural community type).

 

Riparian Wetlands (Lotic Wetlands) - Riparian wetlands are wetlands associated with running water systems found along rivers, streams, and drainage ways. Such wetlands contain a defined channel and floodplain. The channel is an open conduit which periodically, or continuously, carries flowing water, dissolved and suspended material. Beaver ponds, seeps, springs, and wet meadows on the floodplain of, or associated with, a river or stream are part of the riparian wetland.

 

Riparian or Wetland Ecosystem - The ecosystem located between aquatic and terrestrial environments. Identified by hydric soil characteristics and riparian or wetland plant species that requires or tolerates free water conditoins of varying duration.

 

Riparian or Wetland Species - Plant species occurring within the riparian or wetland zone. Obligate riparian or wetland species require the environmental conditions associated with the riparian or wetland zone. Facultative riparian or wetland species are tolerant of these environmental conditions, but also occur in uplands.

 

Riparian Zone - A geographically delineated portion of the riparian ecosystem based on management concerns.

 

Rising Limb Of Hydrograph - The rising portion of the hydrograph resulting from runoff of rainfall or snowmelt.

 

River - Rivers are usually larger than streams. They flow year round, in years of normal precipitation, and when significant amounts of water are not being diverted out of them.

 

Riverbank - That portion of the channel bank cross-section that controls the lateral movement of water.

 

Riverine System - Any wetland or deepwater habitat contained within a channel, with exception of wetlands dominated by trees, shrubs, persistent emergents, emergent mosses, or lichens.

 

Rosgen Stream Classification - A stream classification system developed by Dave Rosgen that groups stream types based on certain geomorphological characteristics (e.g., channel slope, shape, and materials). Useful in predicting a stream’s hydraulic and sediment transport behavior under various conditions and in the application of natural channel design methods in stream restoration work.

 

Roughness Coefficient - A factor in velocity and discharge formulas representing the effect of channel roughness on energy losses in flowing water. Manning’s "n" is a commonly used roughness coefficient.

 

Runoff Coefficient -Includes many factors such as type of cover, soil types, infiltration, evaporation, evapotranspiration, and any moisture condition. The fraction of total rainfall that appears as runoff. Represented as "C" in the rational method formula.

 

 

Safe Drinking Water Act (SDWA) - Originally passed in 1974 to ensure that public water supplies are maintained at high quality. Amendments passed in 1986 require the EPA to set national primary drinking water standards.

 

Salic Horizon – A mineral soil horizon 15 cm (6 in) or more thick enriched with secondary soluble salts.

 

Saline - Soil or water containing sufficient soluble salts to interfere with the growth of most plants.

 

Saturated - A soil condition in which all voids (pore spaces) between soil particles are filled with water.

 

Saturated Condition - "Wet" conditions when media (i.e. watershed basin, soil layer, aquifer, etc.) are fully saturated with water and no infiltration takes place. A condition in which the interstices of a material are filled with a liquid, usually water. It applies whether the liquid is under greater then or less than atmospheric pressure, as long as all connected interstices are full.

 

Saturated Zone - That part of the water-bearing material in which all voids, large and small, are ideally filled with water under pressure greater than atmospheric.

 

Secondary Succession - The process of changing biotic communities that occurs following disturbances to a site that has previously been occupied by living organisms.

 

Sediment - Solid material, such as sand and clay, carried off the land by running water and later deposited in a river, lake, or other waterway. When rainwater runs off the land, it usually carries soil with it on its way to a river or lake.

 

Sediment Control - Practices used on building sites to prevent sand, soil, cement and other building materials from reaching waterways. Even a small amount of pollution from a site can cause significant environmental damage by killing aquatic life, silting up streams and blocking stormwater pipes.

 

Seep - Groundwater discharge areas. In general, seeps have less flow than a spring.

 

Seral - Refers to vegetation that has not theoretically attained a steady state with its environment, and current populations of some species are being replaced by other species; a community or species that is replaced by another community or species as succession progresses.

 

Series - Refers to a group of habitat types having the same climax species.

 

Setback - The distance between a property boundary and a building. A minimum setback is usually required by law.

 

Scrub-Shrub Wetland - A class of wetland habitat which includes areas dominated by woody vegetation less than 6m (20 ft) tall. It may include true shrubs, young trees, or trees or shrubs that are small or stunted because of environmental conditions.

 

Shrub - A multi-stemmed woody plant generally shorter than 4.8 m (16 ft).

 

Silviculture - The branch of forestry dealing with the development and care of forests.

 

Sink - A substance or process that removes a component of concern from the active environment. For example, the adsorption of metals on the surfaces of organic matter serves as a sink for these elements as it removes them from a solution.

 

Slope - Degree of deviation of a surface from the horizontal, measured as a numerical ratio, as a percent, or in degrees. Expressed as a ratio, the first number is the horizontal distance (run) and the second number is the vertical distance (rise), as 2:1. A 2:1 slope is a 50 percent slope. Expressed in degrees, the slope is the angle from the horizontal plane, with a 90 degree slope being vertical (maximum) and a 45 degree slope being a 1:1 slope.

 

Small Mountain Lake - A natural topographic depression collection a body of water covering less than 8 ha (20 acres) with surface water.

 

Soil - A mixture of different inorganic and organic materials. The inorganic fraction consists mostly of fine mineral grains. The percentages by weight of gravel, sand, silt, and clay provide a basis for classifying soil by texture.

 

Soil Conservation Service (SCS) - Now called Natural Resource Conservation Service (NRCS), a branch of the U.S. Department of Agriculture.

 

Soil Erosion - The removal of soil by wind or water.

 

Soil Moisture - Water in the soil mantle, available for use by plants.

 

Soil Series - A subdivision of a soil family that consists of soils that are similar in all major soil profile characteristics and arrangements.

 

Solum - The upper and most weathered part of the soil profile; the A and B horizons.

 

Somewhat Poorly Drained - Water is removed slowly enough that the soil is wet for significant periods during the growing season.

 

Spatial - Describes the characteristics of a given area. For example, the spatial distribution of whales in the ocean or the spatial distribution of aquifer thickness.

 

Spatial Data - Any information about the location, shape of, and relationships among geographic features. This includes remotely sensed data as well as map data.

 

Spatial Variation - Variation (change) of a certain parameter within studied area.

 

Specific Conductance - A measure of the ability of water to conduct an electrical current, expressed in micromhos per centimeter at 25 degrees Celsius. Related to the type and concentration of ions in solution and can be used for approximating the dissolved-solids content of the water. Commonly, the concentration of dissolved solids (in milligrams per liter) is about 65% of the specific conductance (in micromhos). This relation is not constant from supply to supply, and it may even vary in the same source with changes in the composition of the water.

 

Specific Conductivity - With reference to the movement of water in soil, a factor expressing the volume of transported water per unit of time in a given area

 

Spring - Groundwater discharge areas. In general, springs are considered to have more flow than seeps.

 

Stable Community - The condition of little or no perceived change in plant communities that are in relative equilibrium with existing environmental conditions. It describes persistent but not necessarily climax stages in plant succession.

 

Stage - The elevation of a water surface in relation to a datum.

 

Stand - A plant community that is relatively uniform in composition, structure, and habitat conditions; a sample unit.

 

Storm Event  - A rainfall event that produces more than 0.1 inch of precipitation and that which is separated from the previous storm event by at least 72 hours of dry weather.

 

Storm Sewer System  - System of pipes and channels that carry stormwater runoff from the surfaces of building, paved surfaces, and the land to discharge areas.

 

Stream - A natural waterway that is defined as first to third order.

 

Stream Bank - That portion of the channel bank cross-section that controls the lateral movement of water.

 

Stream Channel  - The bed where a natural stream of water runs or may run. The long, narrow depression shaped by the concentrated flow of a stream and covered continuously or periodically by water.

 

Stream Channelization  - A method of flood control in which a river or stream channel is widened, deepened, cleared, strengthened, and/or made more straight.

 

Stream Flow - The flow in natural streams.

 

Stream Order - A classification of streams according to the number of tributaries. Order 1 streams have no tributaries; a stream of Order 2 or higher has 2 or more tributaries of the next lower order.

 

Still Water Wetlands (Lentic Wetlands) - These wetlands occur in basins and lack a defined channel and floodplain. Included are permanent (e.g., perennial) or intermittent bodies of water such as lakes, reservoirs, potholes, marshes, ponds, and stockponds. Other examples include fens, bogs, wet meadows, and seeps not associated with a defined channel.

 

Stockpond - An artificial (dammed) body of water of less than 8 ha (20 ft) covered by surface water.

 

Subterranean Stream - A stream that flows underground for part of the stream reach.

 

Succession - The change or sequence of plant, animal, and microbial communities that successively occupy an area over a period of time. The replacement of one plant community by another over time.

 

Primary succession begins on a bare surface not previously occupied by living organisms, such as a recently deposited gravel bar.

 

Secondary succession occurs following disturbances on sites that previously supported living organisms.

 

Sulfate  - A combination of sulfur in the oxidized state (S6+) and oxygen, and a part of naturally occurring minerals in some soil and rock formations. A common constituent in groundwater and surface water. Sulfate minerals tend to be highly soluble.

 

 

Surface Runoff - Water that runs across the top of the land without infiltrating the soil.

 

All the waters flowing on the surface of the earth, either by overland sheet flow or by channel flow in rills, gullies, streams, or rivers.

 

Suspended Sediment - Very fine soil particles that remain in suspension in water for a considerable period of time without contact with the bottom. Such material remains in suspension due to the upward components of turbulence and currents and/or by suspension.

 

Suspended Sediment Load - Suspended sediment concentration in a given volume of water.

 

Swale - A depression or topographical low area.

 

Swamps - Wetlands covered with water for most or all of the year and characterized primarily by the presence of woody plants. Swamps often occurs close to adjacent rivers, streams, lakes, and other bodies water.

 

Sward - An expanse of grass or grass-like plants.

 

 

Temporal Variation - Variation (change) of a certain parameter within specified time interval.

 

Terrain - A tract or region of the Earth's surface considered as a physical feature, an ecologic environment, or a site of some planned human activity, e.g., an engineering location; or in terms of military science, as in terrain analysis.

 

Terrain Slope - Relationship between elevation and horizontal distance for a given length of the terrain.

 

Topography  - The shape and contour of a surface, especially the land surface or ocean-floor surface, usually characterized by slope, aspect and elevation.

 

Total Dissolved Nitrogen - The dissolved nitrogen in the water column.

 

Total Maximum Daily Loads (TMDL) - The maximum quantity of a particular water pollutant that can be discharged into a body of water without violating a water quality standard. The amount of pollutant is set by the U.S. Environmental Protection Agency.

 

Total Nitrogen - Total nitrogen concentration is the total amount of nitrogen in one liter of water. Total nitrogen includes both dissolved nitrogen in the water column and particulate nitrogen contained in algal cells and in organic detritus such as degrading leaves from trees.

 

Total Organic Carbon (TOC) - A measure of the amount of organic materials suspended or dissolved in water.

 

Total Suspended Solids (TSS) - The weight of particles that are suspended in water. Suspended solids in water reduce light penetration in the water column, can clog the gills of fish and invertebrates, and are often associated with toxic contaminants because organics and metals tend to bind to particles. Total suspended solids are differentiated from total dissolved solids by a standardized filtration process, the dissolved portion passing through the filter. The ability of a chemical substance that has the potential of causing acute or chronic adverse effects in plants, animals, or humans.

 

Tree - A single-stemmed woody plant generally taller than 4.8 m (16 ft).

 

Tributary - The rills, brooks, and streams that flow into a major river.

 

Turbidity - A measure of the cloudiness (reduced transparency) of water, determined by the amount of light reflected by particulate matter in the water.

 

 

Unconsolidated Bottom - A class of wetland or deepwater habitat with at least 25% cover of particles smaller than stones, and with a vegetative cover less than 30%.

 

Unconsolidated Shore  - A class of wetland habitat having three characteristics:

 

Unconsolidated substrates with less than 75% areal cover of stones, boulders, or bedrock,

 

Less than 30% areal cover of vegetation other than pioneering plants, and

 

Any of the following water regimes: irregularly exposed, regularly flooded, seasonally flooded, irregularly flooded, temporarily flooded, intermittently flooded, saturated, or artificially flooded.

 

Unsaturated Conditions - Conditions in soils when infiltration is still possible and media contains both air and water.

 

Unsaturated Zone - The zone between the ground surface and the water table that contains both air and water.  A subsurface zone containing water under pressure less than that of the atmosphere, including water held by capillarity; and containing air or gases generally under atmospheric pressure. This zone is limited above by the land surface and below by the surface of the saturated zone, i.e., the water table.

 

Uplands - Any area that does not qualify as a wetland because the associated hydrologic regime is not sufficiently wet to elicit development of vegetation, soils, and/or hydrologic characteristics associated with wetlands. Such areas occurring in floodplains are more appropriately termed non-wetlands. The elevated lands above a floodplain or other low-lying areas.

 

Upland Habitat - The dry habitat along the sides of a river above a flood plain.

 

Urbanization  - Becoming urban, specifically the concentration of population into towns and cities. Associated with this process is the replacement of pervious surfaces with impervious materials such as asphalt and concrete.

 

 

Vegetated Filter Strip  - Created areas of vegetation designed to remove sediment and other pollutants from surface water runoff by filtration, deposition, infiltration, adsorption, decomposition, and volatilization. An area that maintains soil aeration as opposed to a wetland, which at times exhibits anaerobic soil conditions.

 

Velocity  - A vector measurement of the rate and direction of motion. The scalar absolute value (magnitude) of velocity is speed. Velocity can also be defined as rate of change of displacement or just as the rate of displacement, depending on how the term displacement is used. It is thus a vector quantity with dimension length/time. In the SI (metric) system it is measured in meters per second.

 

Very Long Duration (Flooding) - A duration class in which inundation for a single event is greater than 1 month.

 

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

 

 

Water Cycle  -  Describes the existence and movement of water on, in, and above the Earth. Earth's water is always in movement and is always changing states, from liquid to vapor to ice and back again. The water cycle has been working for billions of years and all life on Earth depends on it continuing to work.

 

Water Mark - A line on vegetation or other upright structures that represents the maximum height reached during a flood, ponding, or inundation event.

 

Water Regime (Nontidal) - Includes the following types:

 

Permanently flooded - water covers the land surface throughout the year in all years. Vegetation is composed of obligate hydrophytes.

 

Intermittently exposed - surface water is present throughout the year except in years of extreme drought.

 

Semipermanently flooded - surface water persists throughout the growing season in most years. When surface water is absent, the water table is usually at or very near the land surface.

 

Seasonally flooded - surface water is present for extended period especially early in the growing season, but is absent by the end of the season in most years. When surface water is absent, the water table is often near the soil surface.

 

Saturated - the substrate is saturated to the surface for extended periods during the growing season, but surface water is seldom present.

 

Temporarily flooded - surface water is present for brief periods during the growing season, but the water table usually lies well below the soil surface for most of the season. Plants that grow both in uplands and wetlands are characteristic of the temporarily flooded regime.

 

Intermittently flooded - the substrate is usually exposed, but surface water is present for variable periods without detectable seasonal periodicity. Weeks, months, or even years may intervene between periods of inundation. The dominant plant communities under this regime may change as soil moisture conditions change. Some areas exhibiting this regime may not fall within the wetland definition because they do not have hydric soils or support hydrophytic plants.

 

Water Table - The upper surface of the zone of saturation within the soil or geologic material.

 

 

Wet Meadow - A herbaceous wetland on mineral soil. Generally, wet meadows occur in seasonally flooded basins and flats. Soils are usually dry for part of the growing season.

 

Watershed -  Land area that drains to a common waterway, such as a stream, lake, estuary, wetland, or ultimately the ocean. The land area drained by a river and its tributaries; also called catchment, drainage area, or river basin.

 

Wetlands - Areas that under normal circumstances have hydrophytic vegetation, hydric soils, and wetland hydrology. It includes landscape unit such as bogs, fens, carrs, marshes, and lowlands covered with shallow, and sometimes ephemeral or intermittent waters. Wetlands are also potholes, sloughs, wet meadows, riparian zones, overflow areas, and shallow lakes and ponds having submerged and emergent vegetation. permanent waters of streams and water deeper than 3 m (approx. 10 ft) in lakes and reservoirs are not considered wetlands. An area that is covered by water at least some part of the year. Sufficient moisture is present so that soil is wet a significant period of time every year. Plants, humans, and other animals have adapted special techniques for surviving in the special environmental conditions present in wetlands.

 

Wetland Hydrology - Permanent or periodic inundation or prolonged soil saturation sufficient to create anaerobic conditions in the soil. Primary wetland hydrology indicators are: inundated, saturated in upper 4.7 cm (12 in), water marks, drift lines, sediment deposits, drainage patterns in wetlands. Secondary wetland hydrology indicators are: oxidized root channels in upper 4.7 cm (12 in), water-stained leaves, local soil survey data, FAC-neutral test (Environmental Laboratory, 1987).

 

Wetland Status - Refers to plant species that have exhibited an ability to develop to maturity and reproduce in an environment where all or portions of the soil within the root zone become, periodically or continuously, saturated or inundated during the growing season. The ability to grow and reproduce in wetlands is due to morphological and/or physiological adaptations and/or reproductive strategies of the plant (Reed 1988a; 1988b). Categories are as follows:

 

OBL (Obligate Wetland). Refers to species that almost always occur (estimated probability greater than 99%) under natural conditions in wetlands.

 

FACW (Facultative Wetland). Refers to species that usually occur in wetlands (estimated probability is 67 - 99%), but is occasionally found in non-wetlands.

 

FAC (Facultative). Refers to species that are equally likely to occur in wetlands or nonwetlands (estimated probability is 34 - 66%).

 

FACU (Facultative Upland). Refers to species that usually occur in non-wetlands (estimated probability is 67 - 99%), but are occasionally found in wetlands (estimated probability is 1 - 33%)