Glossary of Environmental Terms Flashcards
Acid rain
Precipitation with pH levels much below average as a result of the formation of sulfuric acid in polluted air
Active layer
the surface layer in a permafrost environment, which is characterized by freezing and thawing on a seasonal basis
Aggradation
Filling in of a stream channel with sediment, usually associated with low discharges and/or heave sediment loads
Albedo
The percentage of incident radiation reflected by a material.
Alluvial fan
A fan-shaped deposit of sediment laid down by a stream at the foot of a slope; very common features in dry regions, where streams deposit their sediment load as they discharge downstream
Aquifer
Any subsurface material that holds a relatively large quantity of groundwater and is able to transmit that water readily
Backshore
The zone behind the shore – between the beach berm and the back shore slope
Backshore slope
The bank or bluff landward of the shore that is comprised of in situ material
Backswamps
A low, wet area in the floodplain, often located behind a levee
Bankfull discharge
The flow of a river when the water surface has reached bank level
Baseflow
The portion of streamflow contributed by groundwater; it is a steady flow that is slow to change even during rainless periods
Bay-mouth bar
A ribbon of sand deposited across the mouth of a bay
Berm
A low mount that forms along sandy beaches; also used to describe elongated mounds constructed along water features and site borders
Boreal forest
Subarctic conifer forests of North America and Eurasia; floristically homogeneous forests dominated by fir, spruce, and tamarack; in Russia, called taiga
Buildable land units
Parcels of various size within a designated project area that are suitable for development as defined by a prescribed development program
Carrying capacity
The level of development density or use an environment is able to support without suffering undesirable or irreversible degradation
Choropleth map
A map comprised of areas of any size or shape representing qualitative phenomena (e.g. soils) or quantitative phenomena (e.g. population); map often has a patchwork appearance
Climate
The representative or general conditions of the atmosphere at a place on earth; it is more than the average conditions of the atmosphere, for climate may also include extreme and infrequent conditions
Closed forest
A forest structure with multiple levels of growth from the ground up a forest in which undergrowth closes out the area between the canopy and the ground
Coastal dune
A sand dune that forms in coastal areas and is fed by sand from the beach
Colluvium
An unsorted mix of soil and mass-movement debris (accumulates at base of steep slope, for example after landslide)
Conduction
A mechanism of heat transfer involving no external motion or mass transport; instead, energy is transferred through the collision of vibrating molecules
Conveyance zone
The central route of drainage, usually a channel and valley, in drainage basin
Declination of the sun
The location (latitude) on earth where the sun on any day is directly overhead; declinations range from 23.27º S latitude to 23.27º N latitude
Degradation
Scouring and downcutting of a stream channel, usually associated with high discharges
Design storm
A rainstorm of a given intensity and frequency of recurrence used as the basis for sizing stormwater facilities such as storm sewers
Detention
A strategy used in stormwater management in which runoff is detained on site to be released later at some prescribed rate
Development density
A measure of the intensity of development or land use; defined on the basis of area covered by impervious surface, population density, or building floor area coverage, for example
Drainage basin
The area that contributes runoff to a stream, river, or lake
Drainage density
The number of miles (or km) of stream channels per square mile (or square kilometer) of land
Drainage divide
The border for drainage basin or watershed where overland separates between adjacent areas
Drainage network
A system of stream channels usually connected in a hierarchical fashion (see also principle of stream orders)
Drainfield
The network of pipes or tiles through which wastewater is dispersed into the soil
Ecosystem
A group of organisms linked together by a flow energy; also a community of organisms and their environment
Ecotone
The transition zone between two groups, or zones, of vegetation. The boundary of an ecosystem.
Environmental assessment
A preliminary study or review of a proposed action (project) and the influence it could have on the environment. Often conducted to determine the need for more detailed environmental impact analysis
Environmental impact statement
A study required by U.S. Federal law for projects (proposed) involving federal funds to determine types and magnitudes of impacts that would be expected in the natural and human environment and the alternative courses of action, including no action
Ephemeral stream
A stream without baseflow; one that flows only during and after rainstorms or snowmelt events
Environmental inventory
Compilation and classification of data and information on the natural and human features in an area proposed for some sort of planning project
Erodibility
The relative susceptibility of a soil to erosion
Erodibility factor
A value used in the universal soil loss equation for different soil type representing relative erodibility. Called the K-factor by the U.S. Soil Conservation Service
Erosion
The removal of rock debris by an agency such as moving water, wind, or glaciers; generally, the sculpting or wearing down of the land by erosional agents
Eutrophication
The increase of biomass of a waterbody leading to infilling of the basin and the eventual disappearance of open water; sometimes referred to as the aging process of a waterbody
Evapotranspiration
The loss of water from the soil through evaporation and transpiration
Feasibility study
A type of technical planning aimed at identifying the most appropriate use of a site
Fetch
The distance of open water in one direction across a water body; it is one of the main controls of wave size
Floodway fringe
The zone designated by U.S. Federal flood policy as the area in a river valley that would be lightly inundated by the 100-year flood
Frequency
The term used to express how often a specified event is equaled or exceeded
Frost wedging
A mechanical weathering process in which water freezes in a crack and exerts force on the rock, which may result in the breaking point of the rock; a very effective weathering process in alpine and polar environments
Geomorphic system
A physical system comprised of an assemblage of landform linked together by the flow of water, air, or ice
Geomorphology
The field of earth science that studies the origin and distribution of landforms, with special emphasis on the nature of erosional processes; traditionally, a field shared by geography and geology
Grafting
The practice of attaching additional channels to a drainage network; in agricultural areas new channels appear as drainage ditches; in urban areas, as stormsewers
Greenbelt
A tract of trees and associated vegetation in urbanized areas; it may be a park, nature preserve, or part of a transportation corridor
Gross sediment transport
The total quantity of sediment transported along a shoreline in some time period, usually a year
Ground frost
Frost that penetrates the ground in response to freezing surface temperatures
Ground sun angle
The angle formed between a beam of solar radiation and the surface that it strikes in the landscape
Groundwater
The mass of gravity water that occupies the subsoil and upper bedrock zone; the water occupying the zone of saturation below the soil water zone
Gullying
Soil erosion characterized by the formation of narrow steep-sided channels etched by rivulets or small streams of water. Gullying can by one of the the most serious forms of soil erosion of cropland
Habitat
The environment with which an organism interacts and from which it gains its resources; habitat is often variable in size, content, and location, chaining with the phases in an organism’s life cycle
Hardpan
A hardened soil layer characterized by the accumulation of colloids and ions
Hazard assessment
Study and evaluation of the hazard to land use and people from environmental threats such as floods, tornadoes, and earthquakes
Heat island
The area or patch of relatively warm air which develops over urbanized areas
Heat transfer
The flow of heat within a substance or the exchange of heat between substances by means of conduction, convection, or radiation
Hillslope processes
The geomorphic processes that erode and shape slopes; mainly mass movements such as soil creep and landslides and runoff processes such as rainwash and gullying
Hydrograph
A streamflow graph which shows the change in discharge over time, usually hours or days
Hydrograph method
A means of forecasting streamflow by constructing a hydrographic that shows the representative response of a drainage basin to a rainstorm; the use of a “normalized’ hydrographic for flow forecasting in which the size of the individual storm is filtered out
Hydrologic cycle
The planet’s water system, described by the movement of water from the oceans to the atmosphere to the continents and back to the sea
Hydrometer method
A technique used to measure the clay content in a soil sample that involves dispersing the clay particles in water and drawing off samples at prescribed time intervals
In situ
A term used to indicate that a substance is in place as contrasted with one, such as river sediment, that is in transit
Interception
The process by which vegetation intercepts rainfall or snow before it reaches the ground
Interflow
Infiltration water that moves laterally in the soil and seeps into stream channels; in forested areas this water is a major sources of stream discharge
Isopleth map
A map comprised of lines, called isolines, that connect points of equal value
Land cover
The materials such as vegetation and concrete that cover the ground
Landslide
A type of mass movement characterized by slippage of a body of material over a rupture plane; often a sudden and rapid movement
Land use
The human activities that characterize an area, e.g. agricultural, industrial, and residential
Latent heat
The heat released or absorbed when a substance changes phase as from liquid to gas. For water at 0ºC, heat is absorbed or released at a rate of 2.5 million joules per kilogram (597 calories per gram) in a liquid/vapor phase change
Leachate
Fluids that emanate from decomposing waste in a sanitary or chemical landfill
Levee
A mound of sediment that builds up along a river bank as a result of flood deposition
Line scanner
A remote sensing device that records signals of reflected radiation in scan lines that sweep perpendicular to the path (flight line) of the aircraft
Littoral drift
The material that is moved by waves and currents in coastal areas
Loess
Silt deposits laid down by wind over extensive areas of the midlatitudes during glacial and postglacial times
Mass movement
A type of hill slope process characterized by the downslope movement of rock debris under the force of gravity; it includes soil creep, rock fall, landslides, and mudflows; also termed mass wasting
Meander
A bend of loop in a stream channel
Meander belt
The width of the train of active meanders in a river valley
Microclimate
The climate of small spaces such as an inner city, residential area, or mountain valley
Mitigation
A measure used to lessen the impact of an action
Montmorillonite
A type of clay that is notable for its capacity to shrink and expand with wetting and drying
Moraine
The material deposited directly by a glacier; also, the material (load) carried in on on a glacier; as landforms moraines usually have hilly or rolling topography
Mudflow
A type of mass movement characterized by the downslope flow of a saturated mass of clayey material
Multispectral scanning system (MSS)
A line-scanning remote sensing system capable of simultaneously recording reflected radiation in several discrete bands (wavelengths)
Net sediment transport
The balance between the quantities of sediment moved in two (opposite) directions along a shoreline
Nonpoint source
Water pollution that emanates from a spatially diffuse sources such as the atmosphere or agricultural land
Nutrients
Various types of materials that become dissolved in water and induce plant growth; phosphorus and nitrogen are two of the most effective nutrients in aquatic plants
Open forest
A forest structure with a strong upper one or two stories and limited undergrowth; a forest that is largely open at ground level
Open system
A system characterized by a through-flow of material and/or energy; a system to which energy or material is added and released over time
Opportunities and constraints
A type of system often carried out in planning projects to determine the principal advantages and drawbacks to a development program proposed for a particular site
Outflooding
Flooding caused by a stream or river overflowing its banks
Outwash plain
A fluvioglacial deposit comprised of sand and gravel with a flat or gently sloping surface; usually found in close association with moraines
Overland flow
Runoff from surfaces on which the intensity of precipitation or snowmelt exceeds the infiltration capacity
Oxbow
A crescent-shaped lake or pond in a river valley formed in an abandoned segment of channel
Ozone
One of the minor gases of the atmosphere, a pungent, irrigating form of oxygen that performs the important function of absorbing ultraviolet radiation
Parent material
The particulate material in which a soil forms; the two types of parent material are residual and transported
Passive solar collector
A solar collector that operates without the aid of powered machinery
Peak discharge
The maximum flow of a stream or river in response to an event such as a rainstorm or over a period of time such as a year. (Also known as peak flow)
Pedon
The smallest geographic unit of soil defined by soil scientists at USDA
Perennial stream
A stream that receives inflow of groundwater all year; a stream that has a permanent baseflow
Periglacial environment
An area where frost-related processes are a major force in shaping the landscape
Permafrost
A ground-heat condition in which the soil or subsoil is permanently frozen; long-term frozen ground in periglacial environments
Photopair
A set of overlapping aerial photographs that are used in stereoscopic interpretations of aerial photographs
Planned unit development (PUD)
A residential planning strategy aimed at increasing the amount of undeveloped land or common space by clustering development in carefully planned units
Plume
The stream of exhaust (smoke) emanating from a stack or chimney
Point source
Water pollution that emanates from a single source such as sewage plant outfall
Principle of stream orders
the relationship between stream order and the number of streams per order; the relationship of most drainage nets is an inverse characterized by many low-order streams and fewer and fewer streams with increasingly higher orders
Principal point
The center of an aerial photograph, located at the intersection of lines drawn from the fiducial marks on the photo margin
Progradation
The process of seaward growth of a shoreline
Pruning
In hydrology the cutting back of a drainage net by diverting or burying streams; usually associated with urbanization or agricultural development
Quadrat sampling
A field sampling technique in which small plots, called quadrats, are laid out in the landscape and from which the sample is drawn
Radiation
The process by which radiant (electromagnetic) energy is transmitted through free space; the term used to describe electromagnetic energy, basin infrared radiation or shortwave radiation
Rainfall erosion index
A set of values representing the computed erosive power of rainfall based on total rainfall and the maximum intensity of the thirty minute rainfall
Rainfall intensity
The rate of rainfall measured in inches or centimeters of water deposited on the surface per hour or per minute
Rainshadow
a region having little rainfall because it is sheltered from prevailing rain-bearing winds by a range of hills.
Rainsplash
Soil erosion from the impact of raindrops
Rainwash
Soil erosion by overland flow; erosion by sheets of water running over a surface; usually occurs in association with rainsplash
Recharge
The replenishment of groundwater with water from the surface
Recurrence
The number of years on the average that separates events of a specific magnitude, e.g. the average number of years separating river discharges of a given magnitude or greater
Regulatory floodway
A zone designated by the U.S. Federal flood policy as the lowest part of the floodplain where the deepest and most frequent floodplains are conducted
Relief
The range of topographic elevation within a prescribed area
Retention
A strategy used in stormwater management in which runoff is retained on site in basins, underground, or rebased into the soil
Runoff
In the broadest sense runoff refers to the flow of water from the land as both surface and subsurface discharge; the more restricted and common use, however, refers to runoff as surface discharge in the form of overland flow and channel flow
Sapping
An erosional process that usually accompanies gullying in which soil particles are eroded by water seeping from a bank
Scatter diagram
A graph characterized by a series of plotted points showing the relationship between two quantitative variables
Seepage
The process by which groundwater or interflow water seeps from the ground
Septic tank
A vat, usually placed underground, used to store wastewater
Septic system
Specifically, a sewage system that relies on a septic tank to store and/or treat wastewater; generally, an on-site (small-scale) sewage-disposal system that depends on the soil to dispose of wastewater
Sensitive environment
Special environments such as wetlands or coastal lands that require protection from development because of their aesthetic and ecological value
Setback
A term used in site planning to indicate the critical distance that a structure or facility should be separated from an edge such as a back shore slope or lake shore
Shoreland
The discontinuous belt of land around a waterbody that is not drained via stream basins
Side-looking airborne radar (SLAR)
The radar system used in remote sensing; so named because the energy pulse is beamed obliquely on the landscape from the side of the aircraft
Sieve method
A technique used to separate the various sizes of coarse particles in a soil sample
Slope failure
A slope that is unable to maintain itself and fails by mass movement such as a landslide, slump, or similar movement
Slope form
The configuration of a slope, e.g. convex, concave, or straight
Slump
A type of mass movement characterized by a back rotational motion along a rupture plane
Soil creep
A type of mass movement characterized by a very slow downslope displacement of soil, generally without fracturing of the soil mass; the mechanisms of soil creep include freeze-thaw activity and wetting and drying cycles
Solar gain
A general term used to indicate the amount of solar radiation absorbed by a surface or setting in the landscape
Solar heating
The process of generating heat from absorbed solar radiation; a widely used term in the solar energy literature
Stream order
The relative position, or rank, of a stream in a drainage network. Streams without tributaries, usually the small ones, are first-order; streams with two or more first-order tributaries are second-order; etc.
subarctic zone
The belt of latitude between 55º and the Arctic and Antarctic circles
Sun angle
The angle formed between the beam of incoming solar radiation and a plane at the earth’s surface or a plane of the same altitude anywhere in the atmosphere
Sun pocket
A small space designed especially to take advantage of solar radiation and heating
Surge
A large and often destructive wave caused by intensive atmospheric pressure and strong winds
Suspended load
The particles (sediment) carried aloft in a stream of wind by turbulent flow; usually clay and silt-sized particles
Temperate forest
A forest of the midlatitude regions that could be described as climatically temperate, e.g. broadleaf deciduous forests of Europe and North America, comprised of beeches, maples, and oaks
Temperature inversion
An atmospheric condition in which the cold air underlies warm air; inversions are highly stable conditions and thus not conducive to atmospheric mixing
Thermal gradient
The change in temperature over distance in a substance; usually expressed in degrees Celsius per centimeter or meter
Threshold
The level or magnitude of a process at which sudden or rapid change is initiated
Topsoil
The uppermost layer of the soil, characterized by a high organic content; the organic layer of the soil
Tree line
The upper limit of tree growth on a mountain where forest often gives way to alpine meadow
Tundra
Landscape of cold regions, characterized by a light cover of herbaceous plants and underlaid by permafrost
Urban boundary layer
A general term referring to the layer of air over a city that is strongly influenced by urban activities and forms
Urban canyon
City street lined with tall buildings; an urban terrain feature that has a pronounced effect on airflow, radiation and microclimate as a whole
Urban climate
The climate in and around urban areas, it is usually somewhat warmer, foggier, and less well lighted than the climate of the surrounding region
Urbanization
The term used to describe the process of urban development, including suburban residential and commercial development
Wave period
The time it takes a wave to travel the distance of one wavelength
Wave refraction
The bending of a wave, which results in an approach angle more perpendicular to the shoreline
Watertable
The upper boundary of the zone of groundwater; in fine-textured materials it is usually a transition zone rather than a boundary line. The configuration of the water table often approximates that of the overlying terrain
Wetland
A term generally applied to an area where the ground is permanently wet or wet most of the year and is occupied by water-loving or -tolerant vegetation such as cattails, mangrove, or cypress.
The most productive of all ecosystems.
Windshield survey
A rapid and general sampling method for vegetation and land use based on observations from a moving automobile
Zenith
For any location on earth, the point that is directly overhead to an observer. The zenith position of the sun is the one directly overhead
Zenith angle
The angle formed between a line perpendicular to the earth’s surface (at any location) and the beam of incoming solar radiation (on any date)
Marine wetland
Wetland classification if near the open ocean and associated coastline.
Most productive type of wetland and the most sensitive
Estuarine wetland
Wetland classification if near the tidal waters of coastal rivers and embayments, salty tidal marshes, etc.
- Second largest category of U.S. wetlands
Riverine wetland
Wetland classification if near rivers and streams
Lacustrine wetland
Wetland classification if near lakes, reservoir, large ponds, etc.
Palustrine wetland
Wetland classification if near marshes, wet meadows, fens, bogs, swamps, small shallow ponds, etc.
- Large majority of U.S. wetlands are palustrine
Benefits of wetlands
- Coastal wetlands are nursery for shellfish and commercial sport fish
- Habitat for migratory birds
- Storage areas for stormwater runoff and interface for water movement above ground (springs) and below ground (aquifer recharge)
Wetland banking
- Allowed in some jurisdictions for mitigation purposes
Critiques:
- New wetlands do not have same biodiversity
- Unless new wetlands are near destroyed wetlands, wetland banking can alter hydrologic regimes and contribute to flooding
Ephemeral wetland
Wetland in which soils are saturated fora relatively brief period each year
Fen
Peat-forming wetlands that rely on groundwater input.
- Often covered by grasses, sedges, rushes, and wildflowers
- Less acidic, have higher nutrient levels, and can support more wildlife than bogs
Swamp
- Wetlands dominated by woody plants
- Water originates from groundwater or watercourses with the water table well below the surface
Marsh
- Wetlands frequently or continually inundated and dominated by herbaceous plant species
- Plentiful nutrients, pH can be acidic to alkaline
Bog
- Permanently saturated wetland
- Produces peat
- Receive water and nutrients only from atmospheric precipitation (no groundwater) (only occur in areas with abundant rainfall)
Xerophyte
Plants that live in arid, water-scarce conditions. Plant design that reduces/eliminates the need for supplemental water
Mesophyte
Land plants adapted to moderate moisture environments
Hydrophyte
Plants adapted to grow in water or wet conditions (swamps, wetlands, floodplains, etc.)
Stratified sampling
Specific areas chosen beforehand for sampling using such items as aerial photographs. As long as no elements are excluded, this is a viable method of sampling
Systematic sampling
Random sampling method using systematic approach (e.g. sample taken at 15’ intervals off of a line, but the direction of the line at each interval and distance from the interval is random)
Quadrant sampling
Involves setting up individual quadrants throughout the property and everything within the quadrant is recorded
Random sampling
Totally random sampling, unpredictable
Screening for building energy efficiency: sunscreen
- Up to 30% reduction in energy use. Best to locate trees on western and southwestern sides of buildings to reduce heat from summer setting sun
- Plant medium to large trees 15’-30’ away from building (tree should be planted 1/4 to 1/3 mature height away from the building)
Screening for building energy efficiency: windscreen
- Reduce cooling of building in winter by redirecting/blocking cool winds. Evergreen trees located on north and west sides of building
- Effective distance 30x vertical height of the screen. Max. protection exists within 5-6x the height of the screen
- Evergreen windscreens should be three rows thick, deciduous up to 6 rows thick
Gap analysis
Assessment of the extent to which protected area system meets protection goals set by region to represent its biodiversity
USGS topographic map
In additional to topography, USGS topographic maps depict detailed ground relief (landforms and terrain)), drainage (lakes and rivers), forest cover, administrative areas, populated areas, transportation routes and facilities (including roads and railways), and other man-made features. New construction since last printing will generally be shown in purple
(aka quadrangle map)
Thematic map
A thematic map is also called a special-purpose, single-topic, or statistical map. A thematic map focuses on the spatial variability of a specific distribution or theme, whereas a reference map focuses on the location and names of features.
Watershed
A land area that channels rainfall and snowmelt to creeks, streams, and rivers, and eventually to outflow points such as reservoirs, bays, and the ocean.
Hand test (soil field test)
Pick up a handful of soil, squeeze, and open.
If the soil is moldable and breaks into only a couple of pieces when dropped, it has the right amount of moisture for proper compaction
Sand cone test (soil field test)
Compares density of soil that was just compacted to the density obtained from a Proctor test of soil from the same area
Soil modulus (soil stiffness test)
Soil stiffness is the ratio of force-to-displacement.
Desirable engineering property
Machine sends vibrations into the soil and then measures the deflection of the soil from these vibrations replaces soil density testing)
Proctor test (soil test)
For determining compaction. A laboratory method of experimentally determining the optimal moisture content at which a given soil type will become most dense and achieve its maximum dry density.
The Proctor compaction test provides a standardized method of determining a soil’s resistance to compaction over a range of soil water contents under a constant value of compaction energy. The optimum water content (OWC) is the amount of water required to produce a maximum dry density (MDD) from the test procedure.
Soil horizons
O - organic (surface litter) (0-2” below grade)
A - surface (topsoil) (2”-10” below grade)
E - zone of leaching
B - subsoil (10-30” below grade)
C- substratum (partially altered parent material) (30-40” below grade)
R - bedrock (unweathered parent material)
O - C : regolith
O - B: soil
Eluviation
The transport of soil material from upper layers of soil to lower levels by downward percolation of water across soil horizon
Illuviation
The accumulation of soil material (illuvial deposit) in lower levels
Meadow
Periodically inundated wetland that may or may not have water present
Mangrove
A distinct saline woodland or shrubland habitat formed by mangrove trees in brackish tidal water. They are characterized by depositional coastal environments, where fine sediments (often with high organic content) collect in areas protected from high-energy wave action.
Letter of Map Revision (LOMR)
An official revision to the currently effective FEMA map. It is used to change flood elevations, flood zones, floodplain and floodway delineations, and planimetric features
Turbidity
Turbidity is the measure of relative clarity of a liquid.It is an optical characteristic of water and is a measurement of the amount of light that is scattered by material in the water when a light is shined through the water sample. The higher the intensity of scattered light, the higher the turbidity. Material that causes water to be turbid include clay, silt, very tiny inorganic and organic matter, algae, dissolved colored organic compounds, and plankton and other microscopic organisms.
