Environmental Information and Resources

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.

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.

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

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.

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

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

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

Aquifer: A porous, water-saturated layer of sediment and bedrock under the Earth's surface; also described as artesian (confined) or water table (unconfined).

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.

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 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.

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.

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

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.

Chinook: Chinook salmon are the largest of the Pacific salmon, with some individuals growing to more than 100 pounds. These huge fish are rare, as most mature chinook are under 50 pounds. Most chinook spawn in large rivers such as the Columbia and Snake, although they will also use smaller streams with sufficient water flow. 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.

Chum: Male chum salmon develop large "teeth" during spawning, which resemble canine teeth. This may explain the nickname 'dog salmon'. 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.

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

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.

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.

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

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.

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: Use of the petition process to have a facility's toxic designation rescinded.

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.

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.

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

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: 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).

Ecological 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.

Endangered species: A species threatened with extinction.

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. Removal costs in some Oregon parks have reached $2000 per acre. Toxicity of this plant is considerd low but a few scattered reports do exist. Asaponic glycoside is found in the leaves and berries. This is an uncommon poisoning, but incidents have been reported in dogs, cats, and pet monkeys, especially when the green berries were eaten.

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.

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.

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.

Eurasian Watermilfoil: (Myriophyllum spicatum L.) ODA rating: B 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.

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.)

Floodplain: The flat or nearly flat land along a river or stream or in a tidal area that is covered by water during a flood.

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).

Geographic Information System (GIS): A computer system designed for storing, manipulating, analyzing, and displaying data in a geographic context.

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

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: 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 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 in which trenches are cut to a depth greater than 30 centimeters (a foot). Generally, ditches deep enough to cross with farm equipment are considered gullies.

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.

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

Himalayan 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: 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.

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

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

Hydrophilic: Having a strong affinity for water.

Hydrophobic: Having a strong aversion for water.

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.

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.

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.

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

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

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

Knotweed: Polygonum sachalinense and other species. ODA rating: B and T Perennial; blooms July to October. Grows over 12 feett tall. Closely related and similar to Japanese knotweed. Leaf cordate, or heart shaped; often exceeds one foot long. Inflorescence of creamy white flowers sparse, and the flower size does not increase with maturity. Hybrids with Japanese knotweed are common. Japanese knotweed is smaller with truncate leaves. Giant knotweed is the largest of the knotweeds, enabling this species to dominate and out compete native or beneficial plants. It poses a significant threat to riparian areas where it prevents streamside tree regeneration. Research indicates that giant knotweed produces allelochemicals from the roots, which aid in its dominance and rapid colonization. Giant knotweed is a viable pollen source for Japanese knotweed, resulting in male fertile hybrids which are often confused with Japanese knotweed.

Kudzu: Kudzu kills or degrades native and desirable plants by smothering them under a solid blanket of leaves, by girdling woody stems and tree trunks, and by the sheer force of its weight breaking branches or uprooting entire trees and shrubs. Trees covered by kudzu become damaged by its weight during ice events or die from insufficient light. Once established kudzu grows at a rapid rate extending as much as 60 feet per season at a rate of about one foot per day.  Kudzu grows well under a wide range of conditions and soil types. It favors habitats such as forest edges, abandoned fields, roadsides, and disturbed areas where sunlight is abundant. Kudzu grows best where winters are mild, summer temperature are above eighty degrees and annual rainfall is fourty inches or more.

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.

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.

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.

Marbled murrelet: A rare and imperiled bird that nests in ancient forests on the west coast of the U.S.

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.)

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.

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.

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

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.

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

Overland Flow: 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.

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.

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.

Pink Salmon: Male pink salmon develop a large hump on their back during spawning, hence the nickname humpback salmon. 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.

Precipitation: 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.

Purple Loosestrife: Lythrum salicaria, ODA rating: B AKA purple lythrum. Perennial; blooms midsummer. Grows up to 7 ft tall. Upright bushy plant. Flowers pink to purple, possessing 5-6 petals and numerous on a long spike. Spreads by seed and spreading rhizomes that form dense, woody mats. Its showy purple flowers crown a vigorous plant that crowds out marsh vegetation required by wildlife for food and shelter. Decreased waterfowl and songbird production has been well documented in heavily infested marshes.  This former ornamental species can be found along wetlands, stream banks, and shorelines of shallow ponds.

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)/ θc). Refer to Kaufmann et al 2008 for details.

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.

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.

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.

Scotch Broom: (Cytisus scoparius) ODA rating: B Perennial; blooms April to June. Grows 3 to 10 feet tall. Evergreen shrub with many slender, erect, dark green angled branches with small, simple leaves. Abundant small, yellow, pea-shaped flowers. Easily confused with Spanish broom. Spanish broom (S. Junceum) has round stems, very few leaves, and larger yellow flowers.

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

Slope (S): A unitless value equal to the change in elevation divided by the change in lateral position. It is reported as a proportion in this document.

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. This seems to be the most important criteria for choosing a spawning ground, as sockeye adapt to 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.

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 (either volumetric or surface) of water moving through a channel at any point in time. Often measured as cubic feet per second (cfs). There are four basic sources of stream flow. Groundwater flow into the channel is what provides for the base flow, or normal flow of the stream. For perennial streams the water table is at the height of the surface of the stream as shown below. The base flow of the stream is augmented by interflow from the soil moisture zone. At the surface, direct channel precipitation and surface runoff as overland flow contribute to stream flow during and following storms. Under very low velocities water flows through a stream as smooth sheets running parallel to the bed called laminar flow. Laminar flow has an appearance much like that of a deck of cards with the top card jutting forward over those below. The tug of the channel bottom slows the water near the bed with the water nearer the surface flowing somewhat faster.  Only the finest particles kind be detached, so laminar flow is basically nonerosive. Under higher flow velocities, resistance within the flow and that caused by the bed and sides of the channel cause the flow to break down into separate currents. The swirling currents of turbulent flow undergo constant variation in speed and direction of flow. The swirls of water created during turbulent flow are more erosive than laminar flow and help suspend material in the stream. Turbulent flow is the "normal" type of flow in most streams.

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: 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.

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.)

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

Tansy Ragwort: Senecio jacobaea L. 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. See image of Tansy Ragwort below.

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.

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.

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.

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.

Watershed: 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 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.

Yellow Flag Iris: Iris pseudacorus. Yellow flag is a very showy species growing 3-4 feet in height with the most vigorous growth attained in the wettest environments. The leaves are long, flattened and sword-like, typical of most iris. Large plant clumps are formed from the lateral growth of rhizomes sometimes attaining 20 feet in width. It has erect plant stalks with multiple flowers produced on each. Fruit capsules are large, 3-angled and up to 4 inches in length. Disk-like seeds are shed from the capsules throughout the fall and winter. Floating mats of seed can be observed in backwaters and marshes aiding dispersal.  Reproduction can occur asexually through rhizome fragmentation or by seed production. Food storage in this species is unique. Fructan is the main storage compound held in the cells as opposed to starch. This allows the plants to metabolize energy under very low oxygen conditions and may provide cells with a natural anti-freeze for the winter.  An infestation of yellow flag iris presents a dual impact on both human interests and native environments. This plant displaces native plants including sedges and rushes. This can reduce the carrying-capacity of wetlands for waterfowl and disrupt other ecological relationships.  Irrigation canals and flood control ditches can be severely restricted by the physical nature of the plant clumps. Removal can be costly requiring large excavation equipment or herbicides. Control of heavily infested waterways can be cost prohibitive due to the huge volume of plant material needing to be removed. Any rhizome fragments that remain quickly reestablish a population.  Invaded marshes in some eastern states are experiencing a significant displacement of native sedges and rushes with monocultures of iris. Many over-wintering waterfowl species are dependent on sedge and rush seeds as a high-energy food source. Replacement of this food source with yellow flag iris would reduce the carrying capacity of these marshes to sustain waterfowl populations.  A small volume of yellow flag still exists in the nursery trade. A variegated variety is popular with aquatic gardeners and can be found in several catalogs and web sites. The ease with which this plant can be established using rhizome fragments has led to extensive trading among gardeners and aquatic plant enthusiasts. 

From the EPA Glossary of Terms, the UN Glossary of Terms, the Natural Resource Defense Council Glossary of Terms, the Pollution Prevention and Abatement Handbook World Bank Group, Oregon Department of Agriculture, Ritter, Michael E. The Physical Environment: an Introduction to Physical Geography, and the United States Forest Service.