Environmental Resource Glossary

Demeter Design Home

303(d) List: A list of all water quality impaired systems published on a biennial basis by each state and evaluated by the Environmental Protection Agency. The Department of Environment Quality is responsible for the list in Oregon. Find the latest list on our GIS downloads page.

Ablation: The transition of a frozen substance to liquid and vapor, e.g. snow to water to steam.

Absorption: The entrance of water into the soil or rocks by all natural processes.

Abutilon theophrasti or velvetleaf: An annual shrub 1-2.5 meters tall which is native to Asia. Invasive!

Acaena novae-zelandieae or Biddy biddy: A small (less than cm) perennial plant growing in disturbed, well-drained soils. Invasive!

Acid deposition: A complex chemical and atmospheric phenomenon that occurs when emissions of sulfur and nitrogen compounds and other substances are transformed by chemical processes in the atmosphere, often far from the original sources, and then deposited on earth in either a wet or a dry form. The wet forms, popularly called “acid rain,” can fall as rain, snow, or fog. The dry forms are acidic gases or particulates.

Acid rain 1: When strong acids fall from the atmosphere in the form of rain, snow, fog or dry particles. The acid is the result of pollution caused mostly by sulphur oxides and nitrogen oxides that are discharged into the atmosphere by industry. It also is created by burning coal and oil, from the operation of smelting industries and from transportation. In the atmosphere, these gases combine with water vapour to form acids, which then fall back to Earth. The result often kills forests and sterilizes lakes.

Acid rain 2: The precipitation of dilute solutions of strong mineral acids, formed by the mixing in the atmosphere of various industrial pollutants -- primarily sulfur dioxide and nitrogen oxides -- with naturally occurring oxygen and water vapor.

Acidic: The condition of water or soil that contains a sufficient amount of acid substances to lower the pH below 7.0.

Adaptive Management: research and manage according to the results of monitoring.

Acroptilon repens: Russian knapweed, Turkistan thistle, creeping knapweed, mountain bluet, Russian cornflower, hardheads: A mid-sized (less than .5 meters) perennial shrub. Invasive!

Aegilops triuncialis or Goatgrass: A small (less than 30 cm) annual grass which grows in dry rangeland and can hybridize with wheat. Invasive!

Aerobic: Life or processes that require, or are not destroyed by, the presence of oxygen. (See: anaerobic.)

Aggradation: The deposition of sediment and eroded and transported by water. It is synonymous with deposition and the opposite of erosion.

Agropyron repens or Quackgrass: A perennial shrub which grows 1 meter tall and spreads via rhizomes which produce a chemical that can suppress the growth of other plants, it is native to the Mediterranean region. Invasive!

Alevin: Salmonid lifestage where egg sack is attached to post egg emerged juvenile. These fish do not stray far from the redds they emerged from unlike a fry which can travel farther.

Algae: Simple rootless plants that grow in sunlit waters in proportion to the amount of available nutrients, they can affect water quality adversely by lowering the dissolved oxygen in'the water. They are food for fish and small aquatic, animals.

Algal Blooms: Sudden spurts of algal growth, which can affect water quality adversely and indicate potentially hazardous changes in local water chemistry.

Alhagi pseudalhagi or Camelthorn, Caspian manna: A perennial shrub growing to over 1 meter in height. Spreads throughout riparian areas and moist, disturbed sites via rhizomes and is native to the middle east. Invasive!

Alkaline: The condition of water or soil which contains a sufficient amount of alkali substance to raise the pH above 7.0.

Alliaria petiolata or Garlic mustard: A small (less than meter) biennial with purple flowers and a light garlic scent which grows in open areas as well as forested systems. Invasive!

Alluvium: All sediments deposited through hydrologic processes.

Ambrosia arteminiifolia or ragweed: An annual growing to 1 meter tall in ditches and waste areas. Invasive!

Ambrosia tomentosa or Skeletonleaf bursage, bur ragweed, silverleaf, povertyweed: A small (less than 30 cm) perennial shrub which grows in disturbed areas under a variety of conditions. Invasive!

Anadromous: Fish that spend part of their life cycle in the ocean and part in fresh water.

Anaerobic: A life or process that occurs in; or is not destroyed by, the absence of oxygen.

Anastomosing stream: Braiding and successive division and rejoining of stream channels with accompanying islands.

Anchusa officinalis or Common bugloss, Common anchusa, alkanet, bee bread, ox's tongue, starflower, common borage, orchanet, Spanish bugloss, enchusa, lingua bovina, and blue bugloss: A short (less than meter) perennial shrub which invades open grasslands native to the Mediterranean region. Invasive!

Antecedent precipitation index: An baseline index of moisture stored within a watershed before a precipitation event.

Anthropogenic: Human-induced or human-caused, derived from the Greek root anthropos meaning "man."

Appropriation: To allocate a designated amount of resources.

Aquifer: A porous, water-saturated layer of sediment and bedrock under the Earth's surface; also described as artesian (confined) or water table (unconfined); geologic formations that result in natural water collection and storage which can be drawn from to supply a spring.

Area-capacity curve. A graph showing the relation between the surface area of the water in a reservoir and the corresponding volume.

Arid: Regions where precipitation is insufficient in quantity for most crops and where agriculture is impractical without irrigation.

Atmosphere: The envelope of air surrounding the Earth. Most of the total mass of the atmosphere lies within the troposphere and the stratosphere. Most weather events are confined to the troposphere, the lower eight to 12 km of the atmosphere. The ozone layer is found in the stratosphere which typically extends from 10 to 40 km above the Earth.

Backwater 1: The difference between the how much water is dammed behind a temporary object such as a tree and what normally moves through is considered backwater.

Backwater 2: Any water that pools or ponds adjacent to a stream channel that is only filled from a downstream connection (e.g not an oxbow which is connected at both ends or an oxbow lake which is disconnected at both ends).

Bank: The margins of a stream channel through which water flows.

Bank storage: The maximum capacity of the floodplain to absorb water as water rises during a flood.

Bankfull Discharge: Corresponds to the discharge at which channel maintenance is the most effective, that is, the discharge at which moving sediment, forming or removing bars, forming or changing bends and meanders, and generally doing work that results in the average morphologic characteristics of channels.

Bankfull Height: The elevation of the channel at bankfull discharge, measured from the water surface at low flow. This height is determined empirically based on vegetation and channel morphology.

Bankfull stage: Stage at which a stream first overflows its natural banks. See also Bankfull Discharge, Bankfull Height, Bankfull Width, and Floodstage.

Bankfull Width: The width of the channel at bankfull discharge, determined empirically based on vegetation and channel morphology.

Bankfull Width to Depth Ratio (W:D): Defined as the bankfull width divided by the bankfull depth. It is a measure of bank condition, channelization, and floodplain connectivity.

Basalt: A dark igneous rock formed from lava flows.

Base runoff or flow: Sustained or fair weather runoff/flow consisting mostly of groundwater.

Bedload 1: Sediments which move along the bottom of the stream channel.

Bedload 2: The total quanitity of sediment carrying capacity of a stream; the point at which suspended sediments fall from the water column.

Bedded Sediments: All sediments present on the surface of the channel bed.

Best Management Practice (BMP): Methods that have been determined to be the most effective, practical means of preventing or reducing pollution from non-point sources.

Biodegradable: Capable of being broken down by living organisms into inorganic compounds. Ideally all waste should be biodegradable.

Biotic: Of or relating to life.

BODS: The amount of dissolved oxygen consumed in five days by biological processes breaking down organic matter.

Boulder: Stream substrate larger than 25 cm, alternatively substrate larger than a basketball.

Brachypodium sylvaticum or False brome: An old-world perennial grass which can grow in shady forested areas. Invasive!

Brownfields: Abandoned, idled, or under-used industrial and commercial facilities where expansion or redevelopment is complicated by real or perceived environmental contamination.

Bryonia alba or White bryonia, white bryony, wild hops, devil's turnip, and western kudzu: A toxic perennial vine resembling kudzu native to the Mediterranean and middle east which prefers dry rangelands but can survive in a variety of climates. Invasive!

Buddleja davidii or Butterfly bush, summer lilac: A tall (2-3 meters) perennial shrub which prefers riparian areas but can tolerate almost any habitat native to the colder moist parts of China and Japan. Invasive!

Candidate Species: Taxa for which the Fish and Wildlife Service has sufficient biological information to support a proposal to list as endangered or threatened.

Capillary Action: Movement of water through very small spaces due to molecular forces called capillary forces.

Capillary Fringe: The zone above the water table within which the porous medium is saturated by water under less than atmospheric pressure.

Cardaria chalapensis or lens podded whitetop: A perennial shrub which grows to less than meter and is native to central Europe and western Asia. Invasive!

Cardaria draba or white top, hoary cress: A perennial shrub which grows to less than 1 meter tall in disturbed sites and is native to southwest Asia. Invasive!

Carduus acanthoides or Plumeless thistle: A small (less than meter) biennial plant which grows in disturbed areas and open pastures. Invasive!

Carduus nutans or Musk thistle, nodding thistle: A biennial which grows 1-2 meters tall in moist disturbed areas and is native to southern Europe and western Asia. Invasive!

Carduus pycnocephalus or Italian thistle: A small (less than 1meter) biennial native to southern Europe which grows in disturbed sites. Invasive!

Carduus tenuiflorus or slender flowered thistle: A biennial forb which grows to less than meter in height in disturbed sites. Invasive!

Carthamus baeticus or Smooth distaff thistle: A small thistle common in grazing areas. Invasive!

Carthamus lanatus or Woolly distaff thistle: A mid-sized (~1 meter) annual which grows in range and pasture lands. Invasive!

Centaurea diffusa or Diffuse knapweed, white knapweed, spreading knapweed, tumble: A short (less than meter) biennial which grows in riparian areas and disturbed sites native to the Mediterranean region. Invasive!

Centaurea iberica; C. calcitrapa or Iberian or purple starthistle: A tall (up to 2 meters) biennial plant resembling which grows along roadsides. Invasive!

Centaurea stoebe; C. maculosa or Spotted knapweed: A small (less than meter) short-lived perennial. Invasive!

Centaurea virgata or Squarrose knapweed: A small to medium (less than meter tall) perennial plant that grows in rangeland and pastures. Invasive!

CFS: Cubic foot per second; a measure of stream flow. A basketball is ~1 cubic foot.

Chinook: Chinook salmon are the largest of the Pacific salmon, with some individuals growing to more than 100 pounds. Most mature chinook are under 50 pounds and spawn in large rivers. They tend to spawn in the mainstem of streams, where the water flow is high. Because of their size they are able to spawn in larger gravel than most other salmon. Chinook spawn on both sides of the Cascade Range, and some fish travel hundreds of miles upstream before they reach their spawning grounds. Because of the distance, these fish enter streams early and comprise the spring and summer runs. Fall runs spawn closer to the ocean and more often use small coastal streams. All chinook reach their spawning grounds by fall, in time to spawn. Chinook fry rear in freshwater from three months to a year, depending on the race of chinook and the location. Spring chinook tend to stay in streams for a year; fish in northern areas, where the streams are less productive and growth is slower, also tend to stay longer. Rearing chinook fry use mainstems and their tributaries.

Channel: The area through which water naturally flows, rivers, streams, creeks, all flow through channels, alternatively A natural or artificial waterway of perceptible extent that periodically or continuously contains moving water. It has a definite bed and banks, which serve to confine the water.

Chondrilla juncea or rush skeletonweed: A noxious perennial plant growing to 1 meter tall in rangeland and croplands, favoring light textured soils, and is native to Eurasia. Invasive!

Chum (Dog): Male chum salmon develop large teeth during spawning, which resemble canine teeth. Chum use small coastal streams and the lower reaches of larger rivers. They often use the same streams as coho, but coho tend to move further up the watershed and chum generally spawn closer to saltwater. This may be due to their larger size, which requires deeper water to swim in, or their jumping ability, which is inferior to coho. Either way, the result is a watershed divided between the two species, with all the niches filled. Like coho, chum can be found in virtually every small coastal stream in Washington. In Oregon, they are limited to a few streams along the northern coast and lower Columbia River. In the fall, large numbers of chum can often be seen in the lower reaches of these streams, providing opportunities to view wild salmon in a natural environment. Chum fry do not rear in freshwater for more than a few days. Shortly after they emerge, chum fry move downstream to the estuary and rear there for several months before heading out to the open ocean.

Cirsium arvense or Canada thistle, Californian thistle, Canadian thistle, creeping thistle, field thistle, corn thistle, perennial thistle: A perennial thistle that spreads vigorously through rhizomes and seed dispersal in disturbed sites and fields. Invasive!

Cirsium vulgare or bull thistle, common thistle, and spear thistle: A perennial forb which grows 1-2 meters tall in disturbed sites and is native to Eurasia. Invasive!

Clayoquot Sound: One of the last remaining unlogged watersheds on the west coast of Canada's Vancouver Island.

Clematis vitalba or Old man's beard, Traveler's joy: A perennial vine which grows to 30 meters long native to Europe. Invasive!

Climate: The average and extreme meteorological events of a region over time.

Cloudburst: A high intensity bursting and rapid discharge of water in a cloud.

Coastal pelagic: Fish that live in the open ocean at or near the water's surface but remain relatively close to the coast. Mackerel, anchovies, and sardines are examples of coastal pelagic fish.

Cobble: Stream substrate particles between 6 and 25 cm or from a gravel to a basketball.

Coho Salmon: Coho are anandromous salmon meaning they spend part of their lifetime in the ocean and return to freshwater to spawn. Coho have silver sides and dark blue backs. Mature adults have a pronounced red skin color with darker backs and average 28 inches (71 cm) and 7 to 11 pounds (3.2 to 5.0 kg) occasionally reaching 36 pounds (16 kg). Mature females may be darker than males, with both showing a pronounced hook on the nose. Eggs hatch in the late winter or early spring after 6 to 7 weeks in a redd or gravel nest.



Coliform Index: A rating of the purity of water based on a count of fecal bacteria.

Coliform Organism:. Microorganisms found in the intestinal tract of humans and animals. Their presence in water indicates fecal pollution and potentially adverse contamination by pathogens.

Common Reed Grass: Phragmites australis ssp. australis is a large, perennial, clonal grass species with creeping rhizomes and stolons, and terminal, plume-like flowering stalks. Known as common reed this plant has woody hollow stems that can grow 1-4 meters tall with stem diameters of 0.5-1.5 cm. Leaves are 15-40 cm long with an open leaf sheath. Phragmites grows in a wide range of sites that hold shallow water, including roadside ditches, marshes, swamps, brackish estuaries, and alkaline wetlands.

Competence: The ability of a fluid medium, as a stream or the wind, to move and carry particulate matter, measured by the size or weight of the largest particle that can be transported.

Compliance Monitoring: Collection and evaluation of data, including self-monitoring reports, and verification to show whether pollutant concentrations and loads contained in permitted discharges are in compliance with the limits and conditions specified in the permit.

Compost 1: The relatively stable humus material that is produced from a composting process in which bacteria in soil mixed with garbage and degradable trash break down the mixture into organic fertilizer.

Compost 2: A process whereby organic wastes, including food wastes, paper, and yard wastes, decompose naturally, resulting in a product rich in minerals and ideal for gardening and farming as a soil conditioners, mulch, resurfacing material, or landfill cover.

Condensation: The process by which water changes from the vapor state into the liquid or solid state. It is the reverse of evaporation.

Confluence: The point at which two or more bodies of flowing fresh-water join together.

Conium maculatum or Poison hemlock: A toxic aquatic mid-sized (up to 2 meters) biennial that resembles celery, parsley, and carrots which is native to Europe and Asia. Invasive!

Conservation: Preserving and renewing, when possible, human and natural resources. The use, protection, and improvement of natural resources according to principles that will ensure their highest economic or social benefits.

Conservation Easement: Easement restricting a landowner to land uses that that are compatible with long-term conservation and environmental values.

Conventional Tilling: Tillage operations considered standard for a specific location and crop and that tend to bury the crop residues; usually considered as, a base for determining the cost effectiveness of control practices.

Cortaderia jubata; C. selloana or Jubata grass, pampas grass, Andes grass, selloa pampas grass, cortaderia, pink pampas grass, purple pampas grass: A tall (2-8 meters) perennial grass.

Crupina vulgaris or Bearded creeper: A short (less than meter) annual growing on disturbed, non-tilled soils. Invasive!

Cryology: Science of ice and snow.

Cynoglossum officinale or Hounds tongue, gypsy flower: A toxic mid-sized (.5-1 meter) biennial plant which grows in rangelands and open pastures. Invasive!

Cyperus esculentus or yellow nutsedge, Chufa, chufa flatsedge, yellow nutgrass, swampgrass, coco, coco-nut, earth-almond, northern nutgrass, rush nut, tiger nut: A perennial sedge which grows to less than .5 meters tall in moist soils. Invasive!

Cyperus rotundus or Purple nutsedge: A small (less than 1 meter) perennial riparian plant that is resistant to all known controls. Invasive!

Cytisus striatus or Portuguese broom: A perennial evergreen shrub with a spread of up to 7 meters which is native to Europe. Invasive!


Cytisus scoparius or Scotch broom: A tall (1-3 meters) deciduous (evergreen in mild climates) shrub. Invasive!


Deep-seated Landslide: Bedrock landslides that have a surface area greater than .1 km squared, incorporate predominantly parent material in the slide mass, and do not run out long distances.

Delist 1: Use of the petition process to have a facility's toxic designation rescinded.

Delist 2: Have a stream removed from the 303(d) list either because information points to an erroneous listing or because a water quality management plan has been enacted and restoration is occurring.

Delisted Species: A species that has been removed from the Federal list of endangered and threatened wildlife and plants.

Demeter or Ceres: This is the Greek/Roman goddess of agriculture and learning. According to mythology Demeter handed down the knowledge of farming to man and protects hearth and home.

Depression cone: Water drawn from a well draws faster immediately surrounding a well pump than water from deeper in an aquifer forming this shape underground.

Depression storage: The volume of water contained in natural depressions in the land surface, such as puddles.

Desertification: Land degradation in arid, semi-arid and dry sub-humid areas resulting from various factors, including climatic variations and human activities.

Designated Uses: Those water uses identified in state water quality standards that must be achieved and maintained as required under the Clean Water Act. Uses can include cold water fisheries, public water supply, and irrigation.

Dipsacus laciniatus or Cutleaf teasel: A tall (2-3 meters) biennial native to Europe which grows in dry grasslands. Invasive!

Discharge 1: The total outflow (volume of water) of a watershed or pipe. Discharge, streamflow, and runoff refer to water with solids dissolved or mixed in it. Alternatively the volume of water flowing in a given stream at a given place and within a given period of time, usually expressed as cubic meters per second (m3/sec), or cubic feet per second (cfs). Often symbolized as Q.

Discharge: The total release of water or other liquid from an aquifer, watershed, or pipe.

Dissolved Oxygen (DO): The oxygen freely available in water, vital to fish and other aquatic life and for the prevention of odors. DO levels are considered a most important indicator of a water body's ability to support desirable aquatic life. Secondary and advanced waste treatment are generally designed to ensure adequate DO in waste-receiving waters.

Diversion: The taking or redirecting of water.

Downgradient: The direction tht groundwater flows; similar to "downstream" for surface water.

Drainage area: Synonomous with watershed and basin area, may also refer to reservoir capacity, the total area upstream and uphill from a particular low point.

Drawdown 1: The change in aquifer height and pressure by the pumping of groundwater.

Drawdown 2: The release of water from a reservoir.

Dredge 1: Removal of mud from the bottom of water bodies. This can disturb the ecosystem and causes silting that kills aquatic life. Dredging of contaminated muds can expose biota to heavy metals and other toxics. Dredging activities may be subject to regulation under Section 404 of the Clean Water Act.

Dredge 2: A fishing method that utilizes a bag dragged behind a vessel that scrapes the ocean bottom, usually to catch shellfish. Dredges are often equiped with metal spikes in order to dig up the catch.

Drought 1: A naturally-occurring phenomenon that occurs when precipitation is significantly below normal levels, causing water levels to drop and vegetation to die. This extended period of dry weather usually lasts longer than expected and leads to measurable losses for a human community (crop damage, water supply shortage).

Drought 2: A period of deficient precipitation or runoff extending over an indefinite number of days, but with no set standard by which to determine the amount of deficiency needed to constitute a drought.

Drought 3: Weather event that exhibits lack of regular annual rain and/or floods leading to vegetation death and crop productivity loss. Unsatisfactory distribution of precipitation throughout the year may be as effective a factor in causing a drought as a shortage in the total amount, in otherwords you can have record precipitation events followed by extreme flooding and then drought.

Echium plantagineum or Paterson's curse, Salvation Jane, Riverina bluebell: A toxic biennial plant in the Boraginaceae family growing up to 1 meter in height. Invasive!

Ecologicl Entity: In ecological risk assessment, a general term referring to a species, a group of species, an ecosystem function or characteristic, or a specific habitat or biome.

Ecological/Environmental Sustainability: Maintenance of ecosystem components and functions for future generations.

Ecological Impact: The effect that a irian caused or natural activity has on living organisms and their non-living (abiotic) environment.

Ecological Indicator: A characteristic, of an ecosystem that is related to, or derived from, a measure of biotic or abiotic variable, that can provide quantitative information on ecological structure and function. An indicator can contribute to a measure of integrity and sustainability.

Ecological Integrity: A living system exhibits integrity if, when subjected to disturbance, it sustains and organizes self-correcting ability to recover toward a biomass end-state that is normal for that system. End-states other than the pristine or naturally whole may be accepted as "normal and good."

Ecological Risk Assessment: The application of a formal framework, analytical process, or model to estimate the effects of Human actions(s) on a natural resource and to interpret the significance of those effects in light of the uncertainties identified in each component of the assessment process. Such analysis includes initial hazard identification, exposure and dose-response assessments, and risk characterization.

Ecology: The relationship of living things to one another and their environment, or the study of such relationships.

Ecosystem 1: The interacting system of a biological community and its non-living environmental surroundings.

Ecosystem 2: A dynamic and complex system of plant, animal and microorganism communities and their non-living environment all interacting as a functional unit within a defined physical location. The term may be applied to a unit as large as the entire ecosphere, but usually refers to a division thereof.

Ecotone: A habitat created by the juxtaposition of distinctly different habitats; an edge habitat; or an ecological zone or boundary where two or more .ecosystems meet.

Effluent: The discharge of industrial or urban waste material into the environment; the outflow from a lake or river.

Effluent Wastewater, treated or un-treated, that flows out of a treatment plant, sewer, or industrial outfall. Generally refers to wastes discharged into surface waters.

Egeria densa or South American waterweed, Brazillian elodea, Brazilian waterweed, leafy elodea, dense waterweed: A perennial aquatic plant that grows under water and is native to South America. Invasive!

Endangered species: A species threatened with extinction.

ENDANGERED, RARE, OR THREATENED SPECIES: As defined in CEQA Guidelines, § 15380 (California Code of Regulations, title 14, § 15380), (a) “Species” . . . means a species or subspecies of animal or plant or a variety of plant. (b) A species of animal or plant is: (1) “Endangered” when its survival and reproduction in the wild are in immediate jeopardy from one or more causes, including loss of habitat, change in habitat, overexploitation, predation, competition, disease, or other factors; or (2) “Rare” when either: (A) Although not presently threatened with extinction, the species is existing in such small numbers throughout all or a significant portion of its range that it may become endangered if its environment worsens; or (B) The species is likely to become endangered within the foreseeable future throughout all or a significant portion of its range and may be considered "threatened" as that term is used in the Federal Endangered Species Act. (c) A species of animal or plant shall be presumed to be endangered, rare or threatened, as it is listed in: (1) California Code of Regulations, Title 14, § 670.2 or 670.5, or (2) Title 50, Code of Federal Regulations Section 17.11 or 17.12 pursuant to the Federal Endangered Species Act as rare, threatened, or endangered. (d) A species not included in any listing identified in subdivision (c) shall nevertheless be considered to be endangered, rare or threatened, if the species can be shown to meet the criteria in subdivision (b). (e) This definition shall not include any species of the Class Insecta which is a pest whose protection under the provisions of CEQA would present an overwhelming and overriding risk to man as determined by: (1) The Director of Food and Agriculture with regard to economic pests; or (2) The Director of Health Services with regard to health risks.

Endorheic: A watershed where surface waters do not travel to the ocean.

English Ivy: Hedera helix L. - Rapid and massive vegetative growth of English ivy vines reaches to tree tops and woody ornamentals. It also can displace native vegetation on the forest floor. English ivy frequently becomes intertwined with forest shrubs creating difficulties for manual removal or herbicide use.




Environment 1: The sum of all external conditions affecting the life, development and survival of an organism.

Environment 2: All of the external factors, conditions, and influences which affect an organism or a community. Also, everything that surrounds an organism or organisms, including both natural and human-built elements.

Environmental Assessment: An environmental analysis prepared pursuant to the National Environmental Policy Act to determine whether a federal action would significantly affect the environment and thus require a more detailed environmental impact statement.

Environmental Audit: An independent assessment of the current status of a party's compliance with applicable environmental requirements or of a party's environmental compliance policies, practices, and controls.

Environmental/Ecological Risk: The potential for adverse effects on living organisms associated with pollution of the environment by effluents, emissions, wastes, or accidental chemical releases; energy use; or the depletion of natural resources.

Environmental Equity/Justice:Equal protection from_ environmental hazards for individuals, groups, or communities regardless of race, ethnicity, or economic status. This applies to the development, implementation, and enforcement of environmental laws, regulations, and policies, and implies that no population of people-should be forced to, shoulder a disproportionate share of negative environmental impacts of pollution or environmental hazard due to a lack of political or economic strength levels.

Environmental Impact Assessment (EIA): The critical appraisal, both positive and negative, of the likely effects of a proposed project, ,development, activity or policy on the environment.

Environmental Monitoring and Assessment Program (EMAP): A nationwide EPA program designed to monitor water quality and provide technical resources for state and federal agencies to carry out their responsibilities under the Clean Water Act.

Environmental Site Assessment: The process of determining whether contamination is present on a parcel of real property.

Ephemeral: Sporadic flow.

Equisetum telmateia or Giant horsetail: A mid-sized (.5-1 meter) perennial plant resembling asparagus native to Europe and northern Africa. Invasive!

Erosion: The wearing away of land surface by wind, water, glaciers, chemicals, and exposure to the atmosphere. Erosion occurs naturally but can be intensified by land-clearing practices related to farming, residential or industrial development, road building or deforestation.

Escapement: In reference to salmonid smoltification success e.g. the total escapement of juvenile Coho smolts. Also spawning escapement: the total fish which return to their natal streams to spawn.

Estuary 1: Region of interaction between rivers and near-shore ocean waters, where tidal action and river flow mix fresh and salt water. Such areas include bays, mouths of rivers, salt marshes, and lagoons. These brackish water ecosystems shelter and feed marine life, birds, and wildlife. (See: wetlands.)

Estuary 2: A bay or inlet, often at the mouth of a river, in which large quantities of freshwater and seawater mix together. These unique habitats are necessary nursery grounds for many marine fishes and shellfishes.

Euphorbia esula; E. myrsinites or Spurge, myrtle, leafy spurge: Leafy spurge is an aggressive perennial plant that grows less than cm in rangelands and is native to Eurasia. Invasive!

Euphorbia oblongata or oblong spurge, egg leaf spurge: A Euphorbia which grows in moist meadows and roadside ditches. Invasive!

Eurasian Watermilfoil: (Myriophyllum spicatum L.) Perennial, aquatic plant. Purplish red branching stems grow up to five feet long. Feather-like leaves in whorls of four at each node. Male flowers purplish and appear at the end of the flowering stem. Lower, whitish flowers female. Eurasian watermilfoil has significant economic impacts to waterways, irrigation ditches, and drainage canals where it can inhibit flow and increase maintenance costs. It is also a pest of rivers, lakes and ponds were it reduces water quality, impeded recreation and boat access and have adverse impact to fish habitat. Elevated nutrient levels created by erosion, fertilizers or urban effluent create a rapid growth response that can render a waterway clogged within a short period of time. Expensive control projects frequently target this plant across North America.

Eutrophic Lakes: Shallow, murky bodies of water with concentrations of plant nutrients causing excessive production of algae. (See: dystrophic lakes.) Eutrophication 1: The slow aging process during which a lake, estuary, or bay evolves into a bog or marsh and eventually disappears. During the later stages of eutrophication the water body is choked by abundant plant life due to higher levels of nutritive compounds such as nitrogen and phosphorus. Human activities can accelerate the process.

Eutrophication 2: Over-enrichment of a water body with nutrients, resulting in excessive growth of organisms and depletion of oxygen concentration.

Evaporation: The changing of a liquid to a vapor.

Evapotranspiration: The process through which water is drawn from the soil during plant transpiration. See Guttation.

Evolutionarily Significant Unit: A population reproductively distinct and isolated from other populations of the same species and an important component in the evolutionary legacy of the species.

Exorheic: A watershed where surface waters end in the ocean (via other rivers).

Exotic Species: A species that is not indigenous or native to a region. A species that was introduced intentionally or inadvertently by humans and/or human actions.

Fen: A type of wetland that accumulates peat deposits. Fens are less acidic than bogs, deriving most of their water from groundwater rich in calcium and magnesium. (See: wetlands.)

Fender's blue butterfly (Icaricia icarioides fenderi) - Fender's blue butterfly was considered to be extinct until 1989, it is found in only a few sites throughout the Willamette Valley, in wet-pairies and Festuca grass praries. All known populations are found within 33 kilometers (21 miles) of the Willamette River with the current largest populations at Baskett Slough National Wildlife Refuge and at Willow Creek Main Preserve.

Firn snow: Old snow on the top of glaciers, granular and compact but not yet converted into ice. It is a transitional stage between snow and ice. Also called ne've'. The firn line is the highest level to which the fresh snow on a glaciers surface retreats during the melting season. - USGS

Fine sediment: Sediment with a diameter less than 6 mm.

Fish ladder: An artificial series of pools designed to allow fish passage past dams that bar upstream access.

Fish screen: An intentionally placed barrier to passage that prevents native fish from being diverted into fields during irrigation.

Flood: Any relatively high streamflow event that exceeds bankfull as measured by either stream height or discharge quantity.

Floodplain or flood plain: The soil adjacent to the stream channel consisting of sediment deposited by the stream during regular flood events. Often these are surrounded by historical floodplains or terraces.

Flood plane: The position occupied by the water surface of a stream during a particular flood. Also, loosely, the elevation of the water surface at various points along the stream during a particular flood. - USGS

Flood stage: See Bankfull stage, this is the point at which a river overtops its regular channel.

Flow Duration Curve: This shows the average percentage of time that specific daily flows are equaled or exceeded at sites where continuous records of daily flow are available.





Flume: A natural or man-made channel that diverts water.

Fog: fog particles are smaller than 40 micrometers (pm).

Forebay: The area of reservoir that is upstream of the powerhouse.

Frazil ice: Fine, spiricular ice a.k.a lolly ice when salt water is present.

Fry: The salmonid lifestage following alevin characterized by the beginning of feeding.

Gage height: The water-surface elevation as measured at a gaging station. A measurement of stream height from the bottom of the channel to the top of the water's surface.

Gaging (gauging) station: A particular site on a stream, canal, lake, or reservoir where systematic observations of gage height or discharge are obtained. - USGS

Gaining Stream: a body of surface water which is gaining water from the inflow of ground water.

Galega officinalis or Goatsrue, American garden rue, catgut, devil's shoestring, rabbit-pea, horey turkey peas, Virginia pea, Virginia tephrosia, professor weed: A tall (1-2 meters) perennial old-world shrub which is toxic to almost all grazing animals excluding goats. Invasive!

Genista monspessulana or French broom: A tall (1-4 meters) perennial shrub. Invasive!

Geographic Information System or Science (GIS):A computer system designed for storing, manipulating, analyzing, and displaying data in a geographic context. This is also the science of manipulating and analyzing data with geographic information.

Geomorphology: The branch of geology that studies the characteristics and configuration and evolution of rocks and landforms.

Glacier: Snow which has accumulated and condensed/hardened in valleys to form a large permanent ice sheet which moves slowly downslope.

Geranium lucidum or shiny geranium: An annual weed growing up to 0.5 meters and becomes more shade tolerant with increased moisture. Invasive!

Geranium robertianum or Herb Robert, Robert Geranium, Stinky Bob, Red Robin, Fox Geranium: A small (less than cm) smelly annual which commonly invades woodland areas preferring moist sites but with a tolerance for dry climates as well. Invasive!

Gray Water: Domestic wastewater composed of wash water from kitchen; bathroom, and laundry sinks, tubs, .and washers.

Greenhouse Effect: The warming of the Earth's atmosphere attributed to a buildup of carbon dioxide or other, gases; some scientists think that this build-up allows the sun's rays to heat the Earth, while making the infra-red radiation, atmosphere opaque to infra-red radiation, thereby preventing a counterbalancing loss of heat.

Greenhouse Gas: A gas, such as carbon dioxide or methane, which contributes to potential climate change.

Ground Cover: Plants grown to keep soil from eroding.

Ground-Penetrating Radar: A geophysical method that uses high frequency electromagnetic waves to obtain subsurface information.

Ground Water 1: The supply of fresh water found beneath the Earth's surface, usually in aquifers, which supply wells and springs. Because ground water is a major source of drinking water, there is growing concern over contamination from leaching agricultural or industrial pollutants or leaking underground storage tanks.

Ground Water 2: Water in the ground that is in the zone of saturation, from which wells, springs, and ground-water runoff are supplied. - USGS

Ground Water 3: Flow into a stream channel which provides the base or normal flow of the stream.

Ground Water Outflow: That part of the discharge from a drainage basin that occurs through the ground water. The term "underflow" is often used to describe the ground-water outflow that takes place in valley alluvium (instead of the surface channel) and thus is not measured at a gaging station.

Ground Water Under the Direct Influence (UDI) of Surface Water: Any water beneath the surface of the ground with: 1. significant occurence of insects or other microorgarums/ aigae, or large diameter pathogens; 2. significant and relatively rapid shifts in water characteristcs such as turbidity, temperature, conductivity, or pH which closely correlate to clirriatological or surface water conditions. Direct influence is determined for individual sources in accordance with criteria established by a state.

Ground Water Discharge: Ground water entering near coastal waters which has been contaminated by landfill leachate, deep well injection of hazardous wastes, septic tanks, etc.

Gully Erosion: Severe erosion brought on by torrential downpour in which trenches are cut to a depth greater than 30 centimeters.

Guttation: The loss of water in liquid form from the uninjured leaf or stem of the plant, principally through water stomata. - USGS Habitat 1: The place where a population (e.g., human, animal, plant, microorganism) lives and its surroundings, both living and non-living.

Habitat 2: The geographical location(s) and the associated set(s) of environmental conditions that are necessary for the flourishing of a particular type of plant or animal. In other words, their home.

Habitat 3: the natural home of an animal or plant; or the sum of the environmental conditions that determine the existence of a community in a specific place.

Halogeton glomeratus: A toxic small (less than.5 meters) annual native to Asia preferring dry alkaline rangelands and disturbed areas. Invasive!

Hard Water: Alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap from sudsing.

Heracleum mantegazzianum or Giant hogweed: A short-lived perennial shrub native to the Black sea area which can grow up to 3 meters in height. This plant is similar in appearance to but larger than cow parsnip which is native to North America. This carrot relative has been known to induce phyto-toxicity, a condition where skin which comes into contact with the oils of the plant burns when exposed to light. Invasive!

Hieracium pratense; H. piloselloides; H. floribundum; H. pilosella; H. aurantiacum or Hawkweed tall, yellow, meadow, mouse-ear, or king-devil hawkweed, devil's paintbrush: A perennial wetland shrub native to Europe which spreads vigorously via stolons. The yellow flowers resemble those of dandylions. Native hawkweeds lack stolons and exhibit a single flower. Invasive!

Himalayan Blackberry (AKA Armenian Blackberry): (Rubus discolor) ODA rating: B Perennial; blooms June to August. Root buds produce trailing reddish stems with sharp spines that can grow more than 20 ft per season. Leaves alternate, palmate and compound with serrate margins. Flowers five petaled, white to light pink. Fruits aggregate.



Hydrilla: Perennial aquatic plant. Grows rooted to the bottom with long stems that reach water’s surface. Can be monoecious or dioecious. Leaves are 1/16 to 1/8 inch wide, 1/4 to 3/4 inch long and occur in whorls of five. Small, axillary leaf scales are found next to the stem and inserted at the base of the leaf, a character that distinguishes hydrilla from other family members.The nut-like turions (tubers) are a key identifying feature. Egeria densa is similar in appearence but has leaves in whorls of four and does not have turions. Hydrilla is the most serious threat to aquatic ecosystems in temperate climate zones. Dense stands of hydrilla provide poor habitat for fish and other wildlife altering water quality by raising pH, decreasing oxygen, and increasing temperature. Stagnant water created by mats provides good breeding grounds for mosquitoes. Hydrilla interferes with recreational activities such as swimming, boating, fishing, and water skiing and will clog irrigation ditches and intake pipes.

Hydrogeology: The geology of ground water, with particular emphasis on the chemistry and movement of water.

Hydrograph 1: A graphical way of portraying the change in discharge over time, and how it relates to inputs of water and the environment in which the stream is located. The Y-axis of the hydrograph is scaled for discharge, and when investigating the influence of a storm event, precipitation. The X-axis is scaled for time. Discharge is plotted as a line and precipitation as a bar graph. The hydrograph shows discharge starting at its base flow, rising to a peak (the rising limb) and then declining (recessional limb) back to its base flow. This hydrograph is reflecting modification of stream response to precipitation following urbanization.

Hydrograph 2: A graph showing stage, flow, velocity, or other property of water with respect to time. - USGS

Hydrologic budget: An accounting of the inflow to, outflow from, and storage in, a hydrologic unit, such as a drainage basin, aquifer, soil zone, lake, reservoir, or irrigation project. - USGS

Hydrologic Cycle 1: Movement or exchange of water between the atmosphere and earth.

Hydrologic Cycle 2: The circulation of water from the sea, through the atmosphere, to the land, back to the sea by overland and subterranean routes, and in part by way of the atmosphere, including water that is returned to the atmosphere without reaching the sea. - USGS

Hydrologic equation: The equation balancing the hydrologic budget. - USGS

Hydrologic Unit Code (HUC): a classification of watersheds containing an 8 digit code which indicates region (first 2 digits), sub-region (next 2 digits), accounting unit (next 2 digits), and cataloging unit (rightmost 2 digits).

Hydrologically connected roads: Roads that through ditching and culverting increase the total flow of water into the stream system with road beds essentially acting as stream channels.

Hydrology 1: The science dealing with the properties, distribution, and circulation of water.

Hydrology 2: The science encompassing the behavior of water as it occurs in the atmosphere, on the surface of the ground, and underground. The science that relates to the water of the earth. The science treating of the waters of the earth, their occurrence, distribution, and movements. In practice the study of the water of the oceans and the atmosphere is considered part of the sciences of oceanography and meteorology. - USGS

Hydrophilic: Having a strong affinity for water.

Hydrophobic: Having a strong aversion for water.

Hypericum perforatum or St. Johnswort, Klamath weed, goat weed, common St. Johnswort: A toxic perennial which grows to 1 meter in disturbed, well drained sites and is native to Europe. Invasive!

Hypolimnion: The property of thermal stratification in lakes as a result of warm water rising and cold water, which is most dense at just above freezing, sinking. The hypoliminion is the lowest level of temperature in a lake. - USGS

Hypoxia: The depletion of dissolved oxygen in water, a condition resulting from an overabundance of nutrients of human or natural origin that stimulates the growth of algae, which in turn die and require large amounts of oxygen as the algae decompose. It was the most frequently cited direct cause of fishkills in the U.S. from 1980 to 1989.

Impatiens glandulifera or Policeman's helmet: An large (up to 3 meters) annual which grows in riparian areas and is native to India. Invasive!

Impermeable: Not easily penetrated. The property of a material or soil that does not allow, or allows only with great difficulty, the movement or passage of water.

Instream Use: Water use taking place within a stream channel; e.g., hydroelectric power generation, navigation, water quality improvement, fish propagation, recreation.

Intake: The entrance to a turbine unit at a hydroelectric dam.

Integrated Pest Management (IPM): A mixture of chemical and other, nonpesticide, methods to control pests.

Integrated Waste Management: Using a variety of practices to handle municipal solid waste; can include source reduction, recycling, incineration, and landfilling.

Intermittent stream: A stream that only flows seasonally and is dry often during the summer and/or fall.

Irrigation 1: Applying water or wastewater to land areas to supply the water and nutrient needs of plants.

Irrigation 2: The controlled application of water to arable lands to supply water requirements not satisfied by rainfall. - USGS.

Irrigation Efficiency 1: The amount of water stored in the crop root zone compared to the amount of irrigation water applied.

Irrigation Efficiency 2. The percentage of water applied that can be accounted for in soil-moisture increase.

Irrigation Return Flow: Surface and subsurface water which leaves the field following application of irrigation water.

Isatis tinctoria or Dyers woad: A medium sized (less than meter) biennial which grows in open grasslands native to Europe. Invasive!

Isohyetal line (isohyet): A line drawn on a map or chart joining points that receive the same amount of precipitation. - USGS

Kochia scoparia or Kochia, Fire weed, Mexican fire weed: A small (1-2 meters) annual that grows on a variety of disturbed sites. Invasive!

Kudzu:

Laminar flow: Nonerosive flow under very low velocities where water flows through a stream as sheets parallel to the bed.

Landscape Ecology: The study of the distribution patterns of communities and ecosystems, the ecological processes that affect those patterns, and changes in pattern and process over time.

Landslide: Part of a geologic process called “mass wasting”, which is characterized by the downslope movement of material under the force of gravity. Conditions that precipitate landslides include:1. Saturation of soil and rock material with water;2. Vibrations due to earthquakes or blasting;3. Oversteepening of slopes by undercutting (removal of material through erosion or excavation);4. Oversteepening of slopes by addition of material (such as fill) on the upper portions of the slopes; 5. Alternating freezing and thawing.

Large Woody Debris: Wood which naturally accumulates in the stream from falling trees, floods, and landslides helps to shape and control the hydrograph. The debris is also a critical component of salmon habitat providing cover from predation and high flows as well as helping to form spawning grounds.

Lathyrus latifolius or Perennial peavine: A perennial vine native to Europe. Invasive!

Lepidium latifolium or Pepperweed: A mid-sized (up to 2 meters) perennial native to southern Europe and western Asia. Invasive!

Lepidium pubescens or hairy whitetop: A perennial shrub which grows less than meter tall which prefers alkaline soils. Invasive!

Limiting Factor: A condition whose absence 'or excessive concentration, is incompatible with the needs or tolerance of a species or population and which may have a negative influence on their ability to thrive.

Limnology: The study of lakes.

Linaria dalmatica or dalmatian toadflax: A perennial shrub which grows to less than meter tall in arid rangelands, pastures, and railways, and is native to the Dalmatian Coast of Croatia in the Mediterranean region. Invasive!

Linaria vulgaris or yellow toadflax: A perennial shrub which grows less than 1 meter tall and spreads through creeping rhizomes. Invasive!

Listed Species: An endangered species is one that is in danger of extinction throughout all or a significant portion of its range. A threatened species is one that is likely to become endangered in the foreseeable future.

Lithology: Mineralogy, grain size, texture, and other physical properties of granular soil, sediment, or rock.

Littoral Zone: 1. That portion of a body of fresh water extending from the shoreline lakeward to the limit of occupancy of rooted plants. 2. A strip of land along the shoreline between the high and low water levels.

Lythrum salicaria or Purple loosestrife, purple lythrum: An aquatic perennial shrub growing to 2 meters and is native to Europe and Asia. Invasive!





Marbled murrelet: A rare and imperiled bird that nests in ancient forests on the west coast of the U.S. This bird requires undisturbed old growth inland forests to nest in addition to good feeding and rearing habitat in the areas surrounding their nests to raise their young. They return to the sea once they leave the nests.


Losing Stream: A surface stream or lake which is losing water by seepage into the ground.

Mainstem: The main channel of the river in a river basin, as opposed to the streams and smaller rivers that feed into it.

Marsh: 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. (See: wetlands.)

Meander: The path of a stream channel.

Mist: Liquid particles measuring 40 to 500 micrometers (pm), are formed by condensation of vapor. By comparison, fog particles are smaller than 40 micrometers (pm).

Mitigation: Measures taken to reduce adverse impacts on the environment.

Monitoring: Periodic or continuous surveillance or testing to determine the level of compliance with statutory requirements and/or pollutant levels in various media or in humans, plants, and animals.

Monomictic: Lakes and reservoirs which are relatively deep, do not freeze over during winter, and undergo a single stratification and mixing cycle during the year (usually in the fall).

Montreal Protocol: Treaty, signed in 1987, governs stratospheric ozone protection and research, and the production and use of ozone-depleting substances. It provides for the end of production of ozone depleting substances such as CFCS. Under :the Protocol, various research groups continue to assess the ozone layer. The Multilateral Fund provides resources to developing nations to promote the transition to ozone-safe technologies.

Mudflow: A well-mixed mass of water and soil which can give out during precipitation events and behave like a stream of water.

Myriophyllum aquaticum or Parrots feather: An aquatic plant which spreads via rhizomes and is native to South America and the Amazon River basin. Invasive!

Nardus stricta or Matgrass: A long lived perennial bunchgrass which grows well in high elevation wet meadows. Invasive!

National Estuary Program: A program established under the Clean Water Act Amendments of 1987 to develop and implement conservation and management plans for protecting estuaries and restoring and maintaining their chemical, physical, and biological integrity, as well as controlling point and nonpoint pollution sources.

Navigable Waters: Traditionally, waters sufficiently deep and wide for navigation by all, or specified vessels; such waters in the United States come under federal jurisdiction and are protected by certain provisions of the Clean Water Act.

Nitrate: A compound containing nitrogen that can exist in the atmosphere or as a dissolved gas in water and which can have harmful effects on humans and animals. Nitrates in Water can cause severe illness in infants and domestic animals. A plant, nutrient, and inorganic fertilizer, nitrate is found in septic systems, animal feed lots, agricultural fertilizers, manure, industrial waste waters, sanitary landfills, and garbage dumps.

Nitric Oxiide (NO): A gas formed by combustion under high temperature and high pressure in an internal combustion engine; it is converted by sunlight and photochemical processes in ambient air to nitrogen oxide. NO is a precursor of ground-level ozone pollution, or smog.

Nitrification: The process whereby ammonia in wastewater is oxidized to nitrite and then to nitrate by bacterial or chemical reactions.

Nitrite: 1. An intermediate in the process of nitrification. 2. Nitrous-oxide salts used in food preservation.

Nitrogen Dioxide (NO2): The result of nitric oxide combining with oxygen in the atmosphere; major component of photo chemical smog.

Nitrogen Oxide (NOx): The result of photochemical reactions of nitric oxide in ambient air; major component of photochemical smog. Product of combustion from transportation and stationary sources and a major contributor to the formation of ozone in the troposphere and to acid deposition.

Nitrogenous Wastes: Animal or vegetable residues that contain significant amounts of nitrogen.

No Till: Planting crops without prior seedbed preparation, into an existing cover crop, sod, or crop residues, and eliminating subsequent tillage operations.

Non-potable: Water that is unsafe or unpalatable to drink because it contains pollutants, contaminants, minerals, or infective agents.

Nutrient: Any substance assimilated by living things that promotes growth. The term is generally applied to nitrogen and phosphorus in wastewater, but is also applied to other essential and trace elements.

Nutrient Pollution: Contamination of water resources by excessive inputs of nutrients. In surface waters, excess algal production is a major concern.

Nymphoides peltata or Yellow floating heart, Asaza, marshwort, floating heart, or fringed water lily: An aquatic perennial which grows in slack-water systems low in oxygen. Invasive!

Offstream Use: Water withdrawn from surface or groundwater sources for use at another place.

Onopordum acanthium or Scotch thistle: An annual which grows less than 3 meters in moist areas and is native to Asia and Europe. Invasive!

Onopordum tauricum or Taurian thistle, bull cottonthistle: A short lived perennial which grows in desert riparian zones, rangelands, and forest openings and is native to the Greece. Invasive!

Organic Chemicals/Compounds: Naturally occuring (animal or plant-produced or synthetic) substances containing mainly carbon, hydrogen, nitrogen, and oxygen.

Organic Matter: Carbonaceous waste contained in plant or animal matter and originating from domestic or industrial sources.

Organism: Any form of animal or plant life.

Orobanche minor or small broomrape: An annual parasitic plant native to Europe. Invasive!

Outfall: The place where effluent is discharged-into receiving waters.

Overland Flow 1: A land application technique that cleanses waste water by allowing it to flow over a sloped surface. As the water flows over the surface, contaminants are absorbed and the water is collected at the bottom of the slope for reuse.

Overland flow 2: The flow of rainwater or snowmelt over the land surface toward stream channels. After it enters a stream, it becomes runoff. - USGS

Pebble Count: A procedure for evaluating the superficial composition of a channel bed. The general procedure is to measure and tally sediments by size at regularly spaced intervals across the channel. Under the EMAP protocol, samples are taken at 0, 25, 50, 75, and 100% of the wetted width at 21 cross sections per reach. Each sample is visually assigned to a size class. It is assumed that the sediments are log normally distributed within each size class.

Perennial stream: A stream that flows continuously throughout the year.

pH: An expression of both acidity and alkalinity on a scale of zero to 14, with seven representing neutrality; numbers less than seven indicate increasing acidity and numbers greater than seven indicate increasing alkalinity. Acid rain can increase the pH level of the water in a lake, thereby killing all life.

Phragmites australis ssp. australis or Common reed grass giant reed, phragmites, giant reedgrass, Roseau cane, yellow cane: A tall (1-4 meters) perennial riparian grass species which spreads via rhizomes and seed. Not to be confused with similar North American reed grasses, this grass is native to the milder moist climates of Africa, Asia, and Europe. Invasive!



Pink Salmon (AKA Humpback Salmon): Male pink salmon develop a large hump on their back during spawning. This is the smallest of the fall-spawning Pacific salmon. In Washington, pink salmon runs only occur in odd-numbered years. Spawning: Pinks use the mainstems of large rivers and some tributaries, often very close to saltwater. Because their fry move directly to sea after emerging, the closer they spawn to saltwater the better. The shorter journey reduces predation and increases survival. Sometimes pink salmon spawn right in saltwater, avoiding freshwater altogether. Pinks have a very regular life history, living for two years before returning to spawn the next generation. This is why pink runs in Washington only occur every other year; there are no one-year-old or three-year-old fish to establish runs in the other years. As mentioned, pink fry do not rear in freshwater. Immediately after emerging they move downstream to the estuary and rear there for several months before heading out to the open ocean. Because of this, pink fry have no spots, which provide camouflage in streams, but are bright chrome for open water.

Poke Weed - Pokeweed (Phytolacca americana) is an invasive perennial plant native to the eastern United States in the Phytolaccaceae family and grows to 10 feet high. Several toxins have been identified in species of Phytolacca concentrated in the root, fruit, and seed. Also known as inkberry, bloodberry, or pokeroot the raw fruit is poisonous although the cooked fruit is potentially edible (Rutgers - Don't Eat This Unless You are Sure!!!) and the leaves are edible after a twice boil (young shoots are best). The taproot is poisonous and is capable of killing people and livestock. Botanist Mitch Bitxby of the City of Portland Bureau of Environmental Services believes that the entire plant is toxic including the stems, leaves, berries, and roots. Horses, sheep and cattle have been poisoned by eating fresh leaves or green fodder, and pigs have been poisoned by eating the roots.

Polygonum sachalinense; P. polystachyum or Japanese, Himalayan, Giant Knotweed: A tall (3 meters) vigorous perennial which quickly over runs riparian areas native to Eurasia. Invasive!




Pool: A deep reach of a stream. The reach of a stream between two riffles. Natural streams often consist of a succession of pools and riffles. - USGS

Precipitation 1: Any and all forms of water, whether liquid or solid, that fall from the atmosphere and reach the Earth's surface. A day with measurable precipitation is a day when the water equivalent of the precipitation is equal to or greater than 0.2 mm.

Precipitation 2: The discharge of water from the atmosphere to a surface and includes rain, snow, hail, sleet, etc.

Proposed Species: Taxa for which the Fish and Wildlife Service or National Marine Fisheries Service has published a proposal to list as endangered or threatened in the Federal Register.

Pueraria lobata or Kudzu: A vigorous vine native to Japan and Asia which can completely smother anything in its path. Vines can grow up to 30 meters in length with as many as thirty vines growing from a single taproot which can weigh upwards of 300 kg. In warm moist climates common in the southern United States this vine can grow as much as 20 cm per day. Invasive!

See Lythrum salicaria.

Ranunculus ficaria or Lesser celandine, fig buttercup, bulbous buttercup, small crowfoot: A perennial which invades deciduous woods which spreads via bulbs or seeds. Invasive!

Recurrence interval: The average interval of time within which the given flood will be equaled or exceeded once. - USGS

Redd: A gravel or sand bed in which salmonids develop as eggs.

Relative Bed Stability (RBS): A unitless ratio of the geometric mean particle size to the critical bankfull diameter. Together with %SAFN it is the prime indicator of sediment impairment. RBS = Dgm/D*cbf = Dgm/((0.604*Rbf*S*(Cfp/Cft )1/3)/ ?c). Refer to Kaufmann et al 2008 for details.

Reservoir: A pond, lake, or basin, either natural or artificial, for the storage, regulation, and control of water. - USGS

Residual Pool Depth (RP100): Residual pool depth can be conceptualized as what would remain in a channel if all flow ceased. It is equal to the total longitudinal pool area per 100 meters of reach length. It is a flow invariant indicator of hydraulic roughness, bedform complexity, and pool frequency. It is calculated from a minimum of 100 systematic thalweg measurements.

Riffle: A white water section of stream usually with a gradient of greater than 0% and less than 3%. At higher gradients this habitat is usually a rapid or step pool systme.

Riparian Habitat: Areas adjacent to rivers and streams with a differiing density, diversity, and productivity of plant and animal species relative to nearby uplands.

Riparian Rights: Entitlement of a land owner to certain uses of water on or bordering the property, including the right to prevent diversion or misuse of upstream waters. Generally a matter of state law.

Risk: A .measure of the probability that damage to life, health, property, and/or the environment will occur as- a result of a given hazard.

River Basin: The land area drained by a river and its tributaries.

Rorippa sylvestris or Creeping yellow cress: A short (less than.5 meters) perennial shrub. Invasive!

Run-Off: That part of precipitation, snow melt, or irrigation water that runs off the land into streams or other surface-water. It can carry pollutants from the air and land into receiving waters.

Salt Water Intrusion: The invasion of fresh surface or ground water by salt water. If it comes from the ocean it may be called sea water intrusion.

Salvia aethiopis or Mediterranean sage: A short (less than meter) biennial sage which grows in dry pastures and rangelands and is native to southern and southeastern Europe and was introduced in the United States as an alfalfa seed contaminate. Invasive!

Scotch Broom: see Cytisus scoparius.

Sediment: Any non-organic particulate matter, clay, silt, sand, gravel, rock, cobble, boulder, etc. resulting from the weathering and erosion of bedrock.

Silt: Sediment materials composed of fine or intermediate-sized mineral particles.

Silybum marianum or Milk thistle, Blessed thistle, St. Mary’s thistle, and lady’s thistle: A biennial which grows 1-2 meters tall and is native to the Mediterranean region of Europe. Invasive!

Slope (S): The change in elevation divided by the change in lateral position. This can refer either to a hillslope or a stream slope.

Sluiceway: A channel designed to prevent debris from entering turbine units.

Sockeye:Sockeye are unique in that they require a lake to rear in as fry, so the river they choose to spawn in must have a lake in the system. Sockeye utilize a range of water velocities and substrates. Large rivers that supplied sufficient room for spawning and rearing historically supported huge runs of sockeye, numbering into the millions. One such run still exists today on the Adams River in British Columbia, a tributary to the Fraser River. The Canadian government has built viewing platforms for visitors, and annual runs of over a million sockeye are common. Juvenile sockeye rear for one or two years in a lake, although they are also found in the inlet and outlet streams of the lake. Sockeye fry are often preyed on by resident lake fish, and because they use freshwater year-round, they are susceptible to low water quality.


Spotted owl: Strix occidentalis caurina. A reclusive bird, found in the American West, requiring old-growth forest habitat to survive. One theory regarding their population decline, in addition to the harvesting of mature forests is interbreeding with their close cousins the barred owl. The barred owl is lighter and utilizes hard wood forests more than conifer forests therefore their decline has been less rapid than the spotted owl.






Solanum elaeagnifolium or Silver nightshade: A toxic perennial vine which grows on dry rangeland. Invasive!

Sorghum halepense or Johnsongrass: A tall (1-4 meters) perennial shrub which spreads via rhizomes. Invasive!

Spanish Heath, Portuguese heath, Spanish heather, tree heather: A perennial evergreen shrub, growing up to 3 meters tall which prefers moist, acidic soils in disturbed areas and is native to France, Spain, and Portugal. Invasive!

Spartium junceum or Spanish broom: A tall (1-3 meters) deciduous (evergreen in mild climates) shrub. Invasive!

Sphaerophysa salsula or Austrian peaweed: A perennial native to Asia which grows in moist disturbed sites. Invasive!

Steelhead:Steelhead spawn in the spring. They generally prefer fast water in small-to-large mainstem rivers, and medium-to-large tributaries. In streams with steep gradient and large substrate, they spawn between these steep areas, where the water is flatter and the substrate is small enough to dig into. The steeper areas then make excellent rearing habitat for the juveniles. Like Chinook, Steelhead have two runs, a summer run and a winter run. Most summer runs are east of the Cascades, and enter streams in summer to reach the spawning grounds by the following spring. A few western Washington rivers also have established runs of summer Steelhead. Winter runs spawn closer to the ocean, and require less travel time.Steelhead fry emerge from the gravel in summer and generally rear for two or three years in freshwater, occasionally one or four years, depending on the productivity of the stream. Streams high in the mountains and those in northern climates are generally less productive. Due to their faster growth, hatchery Steelhead smolt at one year of age. Fry use areas of fast water and large substrate for rearing. They wait in the eddies behind large rocks, allowing the river to bring them food in the form of insects, salmon eggs, and smaller fish.

Stratigraphy: Study of the formation, composition, and sequence of sediments,whether consolidated or not.

Stratosphere: The portion of the atmosphere 10-to-25 miles above the earth's surface.

Stream Discharge: The volume of water passing through a particular cross-section in a unit of time, measured in units like cubic meters per second or cubic feet per second. The discharge of a perennially flowing stream is provided by the influx of groundwater into the channel. This influx provides what is called the base flow of the stream. Water is added to the stream by runoff from the surrounding terrain during storm events. Discharge(Q) can be expressed as Q = A X V where, A= cross-sectional area V= velocity.

Stream Flow: The amount of water moving through a channel at any point in time. Often measured as cubic feet per second (cfs).

Stream Gage: A station (often maintained by the USGS) which is measures the flow of water.

Stream order: A method of numbering streams as part of a drainage basin network. The smallest unbranched mapped tributary is called first order, the stream receiving the tributary is called second order, and so on. It is usually necessary to specify the scale of the map used. A first-order stream on a 1:62,500 map, may be a third-order stream on a 1:12,000 map. - USGS

Stressors: Physical, chemical, or biological entities that can induce adverse effects on ecosystems or human health.

Subwatershed: Topographic perimeter of the catchment area of a stream tributary.

Superfund: The program operated under the legislative authority of CEJRCLA and SARA that funds and carries out EPA solid waste emergency and long-term removal and remedial activities. These activities include establishing the National Priorities List, investigating sites for inclusion on the list, determining their priority, and conducting and/or supervising cleanup and other remedial actions.

Surface Runoff: Precipitation, snow melt, or irrigation water in excess of what can infiltrate the soil surface and be stored in small surface depressions; a major transporter of non-point source pollutants in rivers, streams, and lakes.

Surface Water: All water naturally open to the atmosphere (rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.)

Suspended solids or suspended sediments: Small particles of solid pollutants that float on the surface of, or are suspended in, sewage or other liquids. They resist removal by conventional means. Clay, silt, or sand in solution in water.

Swamp: A type of wetland dominated by woody vegetation but without appreciable peat deposits. Swamps maybe fresh or salt water and tidal or non-tidal. (See: wetlands.)

Taeniatherum canput-medusae or Medusahead rye: A small (less than.5 meters) annual grass native to Mediterranean region. Invasive!

Tail Water 1: The section of a stream downstream of a pool.

Tail Water 2: The water surface immediately downstream from a dam.

Tail Water 3: The runoff of irrigation water from the lower end of an irrigated field.

Tamarix ramosissima or saltcedar: A perennial shrub preferring streams, canals, and reservoirs in arid climates. These plants can transpire at least 200 gallons of water per day and will often dry up ponds and streams and is native to Eurasia. Invasive!

Tansy Ragwort: Senecio jacobaea. A noxious weed introduced from Europe in the early 1900's, tansy is often spread in contaminated hay. One of the most common causes of poisoning in cattle and horses, caused by consumption of the weed found in pasture, hay or silage. Milk produced by affected cows and goats can contain toxins. Stock does not reject or avoid it in hay or silage; its poisonous alkaloids are unaffected by drying. Honey from tansy ragwort also contains the alkaloids.

Terrace: A historic floodplain.

Thalweg Depth: The thalweg is considered in this document to be the deepest point in the channel when measured at low flow. The mean thalweg depth is calculated from a minimum of 100 systematic measurements throughout the reach.

Thermal stratification or thermocline: upper layer of the lake, known as the epilimnion, in which the water temperature is virtually uniform; stratum below epilimnion known as the thermocline, in which there is a marked drop in temperature per unit of depth; and the lowest stratum is the hypolimnion, in which the temperature from its upper limit to the bottom is nearly uniform.

Till: Sediment that has generally been deposited beneath a glacier, in contrast to sediment deposited outside of or along the edge of the ice, termed stratified drift.

Topography: The physical features of a surface area including relative elevations and the position of natural and man-made (anthropogenic) features.

Total Dissolved Phosphorous: The total phosphorous content of all material that will pass through a filter, which is determined as orthophosphate without prior digestion pr hydrolysis. Also called soluble P. or ortho P.

Total Dissolved Solids (TDS): All material that passes the standard glass river filter; how called total filtrable residue. Term is used to reflect salinity.

Total Maximum Daily Load (TMDL): A calculation of the maximum amount of a pollutant that a waterbody can receive and still meet water quality standards, and an allocation of that amount to the pollutant’s sources. Water quality standards are set by States, Territories, and Tribes. They identify the uses for each waterbody, for example, drinking water supply, contact recreation (swimming), and aquatic life support (fishing), and the scientific criteria to support that use. A TMDL is the sum of the allowable loads of a single pollutant from all contributing point and nonpoint sources. The calculation must include a margin of safety to ensure that the waterbody can be used for the purposes the State has designated. The calculation must also account for seasonal variation in water quality. The Clean Water Act, section 303, establishes the water quality standards and TMDL programs.

Toxicity: The degree to which a substance or mixture of substances can , harm humans or animals. Acute toxicity involves harmful effects in an organism through a single or short-term exposure Chronic toxicity is the ability of a substance or mixture of substances to cause harmful effects over an extended period, usually upon repeated or continuous exposure sometimes lasting for the entire life of the exposed organism. Subchronic toxicity is he ability of the substance to cause effects for more than one year but less than the lifetime of the exposed organism.

Transpiration: The breathing of plants.

Trapa natans or European water chestnut, Singhara Ling, bullnut: An annual aquatic plant which grows in wetlands and mudflats. Invasive!

Tribulus terrestris or puncture vine: An annual that invades pastures, fields, ditches and roadsides and is native of the Mediterranean region. Invasive!

Tributary: The smaller branch of a stream.

Turbidity: 1. Haziness in air caused by the presence of particles and pollutants. 2. A cloudy condition in water due to suspended silt or organic matter. 3. Reduced clarity of water from suspended sediments.

Tussilago farara or Coltsfoot bullsfoot, coughwort, butterbur, foal's foot, horse-foot, horsehoof, foalswort, fieldhove, donnhove: A small (less than 20 cm) old-world perennial plant with bright yellow flowers which resemble dandelions. Common in disturbed areas spreading by rhizomes and seeds which are blown easily by the wind. Invasive!

Urban Runoff Storm water from city streets and adjacent domestic or commercial properties that carries pollutants of various kinds into the sewer systems and receiving waters.

Water Right: In the US, water rights are determined by each state. In Oregon and many western states the rights are assigned by the first in time first in right while in the eastern US most states assign water rights based on proximaty to the stream.

Watershed 1: The land area that drains into a stream; the watershed for a major river may encompass a nummber of smaller watersheds that ultimately combine at a common point.

Watershed 2: Drainage basin or catchment area.

Watershed Approach: A coordinated framework for environmental management that focuses public and private efforts on the highest priority problems within hydrologically-defined geographic areas taking into consideration both ground and surface water flow.

Watershed Area: A topographic area within a line drawn connecting the highest points uphill of a drinking water intake into which overland flow drains.

Weight of Scientific Evidence: Considerations in assessing the interpretation of published information about toxicity quality of testing methods, size and power of study design, consistency of results across studies, and biological plausibility of exposure-response relationships and statistical associations.

Weir: 1. A wall or plate placed in a stream channel to measure the flow of water. 2. A wall or obstruction used to control flow from settling tanks and clarifiers to ensure a uniform flow rate and avoid short-circuiting.

Weir 2: A structure which alters the flow of water; often constructed to increase stream channel complexity or rack off debris floating downstream.

Well: A bored, drilled, or driven shaft, or a dug hole whose depth is greater than the largest surface dimension and whose purpose is to reach underground water supplies or oil, or to store or bury fluids below ground.

Wetlands: An area that is saturated by surface or ground water with vegetation adapted for life under those soil conditions, as swamps, bogs/fens, marshes, and estuaries.

Wildlife Refuge: An area designated for the protection. of wild animals, within which hunting and fishing are either prohibited or strictly controlled.

Xanthium spinosum or Spiny cocklebur: A toxic annual which grows 1-2 meters tall in disturbed areas. Invasive!

Yellow Flag Iris: Iris pseudacorus. Yellow flag iris grows ~1 meter in height and proliferates in warm to temperate wetlands out competeing native rushes that provide seed for over-wintering water fowl. Additionally they provide little to no amphibian habitat and choke potential salmonid ponds. Very few yellow flag iris are sold commercially today as a result of their invasive nature. Do Not Plant This!

Zygophyllum fabago or Syrian bean caper: A small (less than meter) tender perennial adapted to dry climates. Invasive!

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