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Glossary
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Acclimation- response by an animal that enables it to tolerate a change in a single factor (e.g. temperature) in its environment.
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 wet or 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 Mine Drainage:Drainage of water from areas that have been mined for coal of other mineral ores. The water has a low pH because of its contact with sulfur-bearing material and is harmful to aquatic organisms.
Adaptation- adjustments made by animals in respect of their environments. The adjustments may occur by natural selection, as individuals with favorable genetically acquired traits breed more prolifically than those lacking these traits (genotypic adaptation), or they may involve non-genetic changes in individuals, such as physiological modification (e.g. acclimatization) or behavioral changes (phenotypic adaptation).
Advanced Wastewater Treatment:Any treatment of sewage that goes beyond the secondary or biological water treatment stage and includes the removal of nutrients such as phosphorus and nitrogen and a high percentage of suspended solids. (See primary, secondary treatment.)
Aerobic:Life or processes that can occur only in the presence of oxygen.
Agricultural Pollution:The liquid and solid wastes from all types of farming, including runoff from pesticides, fertilizers and feedlots; erosion and dust from plowing, animal manure and carcasses and crop residues and debris.
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 Bloom:An episode of excessive nutrient content in a river, stream or lake, which causes a proliferation of living algae. The end result is a depletion of much needed oxygen in the water. Excessive algae blooms can lead to the death of the fish and aquatic organisms of the given waterbody through oxygen deprivation called a "fish kill".
Alkaline:The condition of water or soil that contains a sufficient amount of alkali substance to raise the pH above 7.0.
Alkalinity:The capacity of water to neutralize acids.
Anaerobic:Life or processes that occur in the absence of oxygen.
Aquatic Assemblage- an organism group of interacting populations in a given waterbody, for example, fish assemblage or a benthic macroinvertebrate assemblage.
Aquatic Biota -collective term describing the organisms living in or depending on the aquatic environment.
Aquatic Community- association of interacting assemblages in a given waterbody, the biotic component of an ecosystem (see also aquatic assemblage).
Aquatic Life Use- a beneficial use designation in which the waterbody provides suitable habitat for survival and reproduction of desirable fish, shellfish, and other aquatic organisms.
Aquatic Plants:Plants that grow in water either floating on the surface, growing up from the bottom of the body of water or growing under the surface of the water.
Aquifer:An underground bed or stratum of earth, gravel or porous stone that contains water.
Attribute- a measurable component of a biological system.
Bacteria:Single-celled microorganisms that lack chlorophyll. Some bacteria are capable of causing human, animal or plant diseases, others are essential in pollution control because they break down organic matter in the air and water.
Benthic marcroinvertebrates- see benthos.
Benthic Region:The bottom of a body of water. This region supports the benthos, a type of life that not only lives upon, but also contributes to the character of the bottom.
Benthos- The name used to describe the plants and animals (without backbones) living in the streambed or benthic zone, a size large enough to be seen by the unaided eye, and which can be retained by a U.S. Standard No. 30 sieve (28 openings/inch, 0.595-mm openings). Also referred to as bentic macroinvertebrates, infauna, or macrobenthos.
Best Management Practice (BMP):Methods that have been determined to be the most effective, practical means of preventing or reducing pollution from nonpoint sources.
Bioaccumulants:Substances that increase in concentration in living organisms as they take in contaminated air, water, or food because the substances are very slowly metabolized or excreted. (See: biological magnification.)
Bioavailability- degree to which chemicals can be taken up by organisms.
Biochemical Oxygen Demand (BOD):A measure of the amount of oxygen consumed in the biological processes that break down organic matter in water. The greater the BOD, the greater the degree of pollution.
Bioconcentration:The accumulation of a chemical in tissues of an organism (such as a fish) to levels greater than in the surrounding medium in which the organism lives.
Biodegradable:Capable of decomposing rapidly under natural conditions.
Biodiversity:Refers to the variety and variability among living organisms and the ecological complexes in which they occur. Diversity can be defined as the number of different items and their relative frequencies. For biological diversity, these items are organized at many levels, ranging from complete ecosystems to the biochemical structures that are the molecular basis of heredity. Thus, the term encompasses different ecosystem, species, and genes.
Biological Assessments or Bioassessments- evaluation of the biological condition of a waterbody using biological surveys and other direct measurements of resident biota in surface waters.
Biological Criteria or Biocriteria- narrative or numeric expressions that describe the biological condition (structure and function) of aquatic communities inhabiting waters of a designated aquatic life use. Biocriteria are based on the numbers and kinds of organisms present and are regulatory-based biological measurements.
Biological Integrity- the ability of an aquatic ecosystem to support and maintain a balanced, adaptive community of organisms having a species composition, diversity, and functional organization comparable to that of natural habitats within a region.
Biological Magnification:Refers to the process whereby certain substances such as pesticides or heavy metals move up the food chain, work their way into rivers or lakes, and are eaten by aquatic organisms such as fish, which in turn are eaten by large birds, animals or humans. The substances become concentrated in tissues or internal organs as they move up the chain. (See: bioaccumulative.)
Biological Monitoring or Biomonitoring- use of a biological entity as a detector and its response as a measure to determine environmental conditions. Toxicity tests and ambient biological surveys are common biological monitoring methods.
Biological Survey or Biosurvey- collecting, processing, and analyzing a representative portion of the resident aquatic community to determine its structural and/or functional characteristics.
Bioregion- any geographical region characterized by a distinctive flora and fauna (see also ecoregion).
Biome:Entire community of living organisms in a single major ecological area. (See: biotic community.)
Biota:The animal and plant life of a given region.
Biotic Community:A naturally occurring assemblage of plants and animals that live in the same environment and are mutually sustaining and interdependent. (See: biome.)
Bloom (algal):A proliferation of algae and/or higher aquatic plants in a body of water; often related to pollution, especially when pollutants accelerate growth.
Bog:A type of wetland that accumulates appreciable peat deposits. Bogs depend primarily on precipitation for their water source, and are usually acidic and rich in plant residue with a conspicuous mat of living green moss.
Brackish:Mixed fresh and salt water.
Buffer:A solution or liquid whose chemical makeup neutralizes acids or bases without a great change in pH.
Buffer Strips:Strips of grass or other erosion-resisting vegetation between or below cultivated strips or fields.
Channel:A stream or riverbed.
Channelization:The straightening and deepening of streams to permit water to move faster, to reduce flooding or to drain marshy acreage for farming. However, channelization reduces the organic waste assimilation capacity of the stream and may disturb fish breeding and destroy the stream's natural beauty.
Chlorophyll:A chemical mixture or compound found in the chloroplasts of plant cells and gives plants their green color. Plants use chlorophyll to convert the energy of sunlight to food in the process known as photosynthesis.
Clean Water Act (CWA)- An act passed by the U.S. Congress to control water pollution (formerly referred to as the Federal Water Pollution Control Act of 1972). Public Law 92-500, as amended. 33 U.S.C. 1251 et seq.
Clean Water Act Section 303(d)- annual report to Congress from EPA that identifies those waters for which existing controls are not sufficiently stringent to achieve applicable water quality standards.
Clean Water Act Section 305(b)- biennial reporting requires description of the quality of the Nation's surface waters, evaluation of progress made in maintaining and restoring water quality, and description of the extent of remaining problems by using biological data to make aquatic life use support decisions.
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.
Collector Sewers:Pipes used to collect and carry wastewater from individual sources to an interceptor sewer that will carry it to a treatment facility.
Combined Sewer Overflows:Discharge of a mixture of storm water and domestic waste when the flow capacity of a sewer system is exceeded during rainstorms.
Combined Sewers:A sewer system that carries both sewage and storm-water runoff. Normally, its entire flow goes to a waste treatment plant, but during a heavy storm, the volume of water may be so great as to cause overflows of untreated mixtures of storm water and sewage into receiving waters. Storm-water runoff may also carry toxic chemicals from industrial areas or streets into the sewer system.
Community:In ecology, a group of interacting populations in time and space. Sometimes, a particular subgrouping may be specified, such as the fish community in a lake or the soil arthropod community in a forest.
Consumer:A heterotrophic organism in a food chain that ingests other organisms or organic matter.
Criteria- statements of the conditions presumed to support or protect the designated use or uses of a waterbody. Criteria may be narrative or numeric.
Cultural Eutrophication:Acceleration by man of the natural aging process of bodies of water.
Current:The segment of a stream, river, or other waterbody that moves with a velocity much greater than the average of the rest of the water.
Density-Dependence- regulation of the size of a population by mechanisms that are themselves controlled by the size of that population (e.g. the availability of resources) and whose effectiveness increases as population size increases.
Designated Use- classification specified in water quality standards for each waterbody or segment describing the level of protection from perturbation afforded by the regulatory programs. The designated aquatic life uses established by the state or authorized tribes set forth the goals for restoration and/or baseline conditions for maintenance and prevention from future degradation of the aquatic life in specific waterbodies.
Detritus:Loose fragments, particles, or grains formed by the disintegration of rocks.
Diatom- microscopic algae with cell walls made of silicon and have two separating halves.
Dissolved Oxygen (DO):The oxygen dissolved in water or sewage. Adequately dissolved oxygen is necessary for the life of fish and other aquatic organisms and for the prevention of offensive odors.
Dredging:A method for deepening streams, swamps or coastal waters by scraping and removing solids from the bottom. The resulting mud is usually deposited in marshes in a process called filling. Dredging and filling can disturb natural ecological cycles. For example, dredging can destroy oyster beds and other aquatic life; filling can destroy the feeding and breeding grounds for many fish species.
Ecology:The interrelationships of living things to one another and to their environment or the study of such interrelationships.
Ecological Integrity- the condition of an unimpaired ecosystem as measured by combined chemical, physical (including physical habitat), and biological attributes.
Ecoregions- a relatively homogeneous ecological area defined by similarity of climate, landform, soil, potential natural vegetation, hydrology, or other ecologically relevant variables (see also bioregions).
Ecosystem:The interacting system of a biological community and its non-living environment.
Effluent:A discharge of pollutants into the environment, partially or completely treated or in its natural state. Generally used in regard to discharges into waters.
Emission:A discharge of pollutants into the environment, partially or completely treated or in its natural state. Generally used in regard to discharges into the air.
Enrichment:The addition of nitrogen, phosphorus and carbon compounds or other nutrients into a lake or other waterway that greatly increases the growth potential for algae and other aquatic plants. Most frequently, enrichment results from the inflow of sewage effluent or from agricultural runoff.
Environment:The sum of all external conditions and influences affecting the life, development and, ultimately, the survival of an organism.
Erosion:The wearing away of the land surface by wind or water. Erosion occurs naturally from weather or runoff but is often intensified by man's land-clearing practices.
Estuaries:Areas where the fresh water meets salt water. For example, bays, mouths of rivers, salt marshes and lagoons. Estuaries are delicate ecosystems; they serve as nurseries, spawning and feeding grounds for a large group of marine life and provide shelter and food for birds and wildlife.
Eutrophic Lakes:Shallow lakes weed-choked at the edges and very rich in nutrients. The water is characterized by large amounts of algae, low water transparency and low dissolved oxygen.
Eutrophication:The normally slow aging process by which a lake evolves into a bog or marsh and ultimately assumes a completely terrestrial state and disappears. During eutrophication the lake becomes so rich in nutritive compounds, especially nitrogen and phosphorus, that algae and other microscopic plant life become superabundant, thereby "choking" the lade, and causing it eventually to dry up. Eutrophication may be accelerated by human activities.
Evaporation:The changing of a substance from a liquid to a gas; evaporation generally occurs when the molecules of a liquid are broken apart by heat. In the water cycle, water evaporates from land, plants and waterbodies and enters the atmosphere as water vapor.
Fecal Coliform Bacteria:A group of organisms common to the intestinal tracts of man and of animals. The presence of fecal Coliform bacteria in water is an indicator of pollution and of potentially dangerous bacterial contamination.
Filamentous:Slender and or threadlike. Filamentous is a term used to describe the slender, sometimes transparent stems of algae.
Fish Kill:When aquatic life within a river, lake, or stream dies in a mass extinction.
Floodplain:A strip of relatively level land bordering a stream or river subject to flooding. Floodplain build up over time by deposits of sediment carried in flood waters.
Fungi:Small, often microscopic plants without chlorophyll. Some fungi infect and cause disease in plants or animals; other fungi are useful in stabilizing sewage or in breaking down wastes for compost.
Game Fish:Those species of fish sought by sports fisherman (trout, bass, salmon, etc). Game fish are usually more sensitive to environmental changes and water quality degradation than "rough" fish.
Groundwater:The supply of freshwater under the earth's surface in an aquifer or soil that forms the natural reservoir for man's use.
Groundwater Runoff:Groundwater that is discharged into a stream channel as spring or seepage water.
Habitat- a place where the physical and biological elements of ecosystems provide a suitable environment including the food, cover, and space resources needed for plant and animal livelihood.
Historical Data - data sets from previous studies, which can range from handwritten field notes to published journal articles.
Hydrologic Cycle:The movement of water in all of its phases (gas, liquid, solid) from the Earth to the atmosphere and back to the Earth.
Hydrology:The science dealing with the properties, distribution and circulation of water and snow.
Hydrophytic Vegetation:Vegetation that only grows in water or substrate that is at least periodically deficient in oxygen during a growing season as the result of excessive water content. Hydrophytes have poorly developed root systems and weak stems; they rely upon the water for support.
Impact- change in the chemical, physical (including habitat) or biological quality or condition of a waterbody caused by external sources.
Impairment - detrimental effect on the biological integrity of a waterbody caused by an impact that prevents attainment of the designated use.
Impoundment:A body of water, such as a pond, confined by a dam, dike, floodgate or other barrier.
Index of Biological Integrity (IBI)- an integrative expression of site condition across multiple metrics. An index of biological integrity is often composed of at least seven metrics. The plural form is either indices or indexes.
Infiltration:The flow of a fluid into a substance through pores or small openings. Commonly used to in hydrology to denote the flow of water into soil material.
Irrigation:Applying water or wastewater to land areas to supply the water and nutrient needs of plants.
Irrigation Return Flow:Surface and subsurface water that leaves the field following application of irrigation water.
Lagoon:A shallow pond where sunlight, bacterial action, and oxygen work to purify wastewater; also used for storage of wastewater or spent nuclear fuel rods. Shallow body of water, often separated from the sea by coral reefs or sandbars.
Limnology:The study of the physical, chemical, meteorological and biological aspects of fresh waters.
Littoral:Of, relating to, or existing on a shore.
Macroinvertebrates- animals without backbones of a size large enough to be seen by the unaided eye and which can be retained by a U.S. Standard No. 30 sieve (28 meshes per inch, 0.595 mm openings).
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.)
Mesotrophic:Reservoirs and lakes that contain moderate quantities of nutrients and are moderately productive in terms of aquatic animal and plant life.
Metalimnion:The middle layer of a thermally stratified lake or reservoir. In this layer there is a rapid decrease in temperature with depth. Also called thermocline.
Metric- A calculated term or enumeration representing some aspect of biological assemblage, function, or other measurable aspect and is a characteristic of the biota that changes in some predictable way with increased human influence. A multimetric approach involves combinations of metrics to provide an integrative assessment of the status of aquatic resources.
Microinvertebrates - animals without backbones that are not large enough to be seen by the unaided eye; they will not be retained by a U.S. Standard No. 30 sieve (28 meshes per inch, 0.595 mm openings).
MinimallyImpaired - sites or conditions with slight anthropogenic perturbation relative to the overall region of the study.
Mitigation:Measures taken to reduce adverse impacts on the environment.
Monomictic:Lakes and reservoirs which are relatively deep, do not freeze over during the winter months, and undergo a single stratification and mixing cycle during the year (usually in the fall).
Multimetric- analysis techniques using several measurable characteristics of a biological assemblage.
Multivariate Community Analysis - statistical methods (e.g. ordination or discriminant analysis) for analyzing physical and biological community data using multiple variables.
Municipal Discharge:Discharge of effluent from waste water treatment plants, which receive waste water from households, commercial establishments, and industries in the coastal drainage basin. Combined sewer/separate storm overflows are included in this category.
Municipal Sewage:Wastes (mostly liquid) originating from a community; may be composed of domestic wastewaters and/or industrial discharges.
Narrative Biological Criteria- general statements of attainable or attained conditions of biological integrity and water quality for a given designated aquatic life use.
National Pollutant Discharge Elimination System (NPDES):A provision of the Clean Water Act which prohibits discharge of pollutants into waters of the United States unless a special permit is issued by EPA, a state, or, where delegated, a tribal government on an Indian reservation.
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.
Neutralization:Decreasing the acidity or alkalinity of a substance by adding alkaline or acidic materials, respectively.
Nitrate:Plant nutrient and inorganic fertilizer that enters water supply sources from septic systems, animal feed lots, agricultural fertilizers, manure, industrial waste waters, sanitary landfills and garbage dumps.
Nitrification:The process whereby ammonia in wastewater is oxidized to nitrite and then to nitrate by bacterial or chemical reactions.
Nitrogenous Wastes:Animal or vegetable residues that contain significant amounts of nitrogen.
Non-Point Source:Diffuse pollution sources (i.e., without a single point of origin or not introduced into a receiving stream from a specific outlet). The pollutants are generally carried off the land by storm water. Common nonpoint sources are agriculture, forestry, urban, mining, construction, dams, channels, land disposal, saltwater intrusion, and city streets.
Non-Point Source Pollution- pollution that occurs when rainfall, snowmelt, or irrigation runs over land or through the ground, picks up pollutants, and deposits them into rivers, lakes, and coastal waters or introduces them into ground water.
NPDES - National Pollutant Discharge Elimination System.
Numeric Biocriteria - numerical indices that describe expected attainable community attributes for different designated aquatic life uses.
Nutrients:Any substance assimilated by living things that promotes growth. Elements or compounds essential as raw materials for organism growth and development; for example, carbon, oxygen, nitrogen and phosphorus. The term is generally applied to nitrogen and phosphorus in wastewater.
Nutrient Pollution:Contamination of water resources by excessive inputs of nutrients. In surface waters, excess algal production is a major concern.
Oligotrophic Lakes:Deep lakes that have a low supply of nutrients and thus contain little organic matter. Such lakes are characterized by high water transparency and high dissolved oxygen.
Organic Chemicals/Compounds:Animal or plant-produced 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 living thing. All organisms are comprised of one or more cells, eat, and reproduce.
Particulates:Finely divided solid or liquid particles in the air or in an emission. Particulates include dust, smoke, fumes, mist, spray and fog.
Peat:Partially decomposed organic material.
Percolation:The passage of liquids, powders or small particles through a porous substance. Water percolates through soil in the water cycle.
Periphyton:Sessile organisms that live attached to the surface projecting from the bottom in a freshwater aquatic environment
Pesticide:An agent used to control pests. This includes insecticides for use against harmful insects; herbicides for weed control; fungicides for control of plant diseases; rodenticides for killing rats, mice, etc.; and germicides used in disinfectant products, algaecides, slimicides, etc. Some pesticides can contaminate water, air or soil and accumulate in man, animals and the environment, particularly if they are misused. Certain of these chemicals have been shown to interfere with the reproductive processes of predatory birds and possibly other animals.
pH:A measure of the acidity pr alkalinity of a material, liquid or solid. pH is represented on a scale of 0 to 14 with 7 representing a neutral state, 0 representing the most acid and 14, the most alkaline.
Phytoplankton:Very tiny, often microscopic, plants found in fresh and saltwater. Phytoplankton drift near the surface of the water where there is plenty of sunlight for growth. Phytoplankton form the basis for all food chains.
Plankton:The floating or weakly swimming plant and animal life in a body of water, often microscopic in size.
Point Source- origin of a pollutant discharge from a discrete conveyance typically thought of as an effluent from the end of a pipe.
Pollutant:Any introduced gas, liquid or solid that makes a resource unfit for a specific purpose.
Pollution:The presence of matter or energy whose nature, location or quantity produces undesired environmental effects.
Population- aggregate of individuals of a biological species that are geographically isolated from other members of the species and are actually or potentially interbreeding.
PotableWater:Water suitable for drinking or cooking purposes from both health and aesthetic considerations.
Precipitation:Water droplets or ice particles- in the form of rain or snow, condensed from atmospheric water vapor.
Predation:The act or practice of capturing another creature (prey) as a means for securing food.
Raw Sewage:Untreated domestic or commercial waste water.
Receiving Waters:Rivers, lakes, oceans or other bodies that receive treated or untreated waste waters.
Reference Condition- set of selected measurements or conditions of unimpaired or minimally impaired waterbodies characteristic of a waterbody type in a region.
Reference Site - specific locality on a waterbody which is unimpaired or minimally impaired and is representative of the expected biological integrity of other localities on the same waterbody or nearby waterbodies.
Regionalization or Ecoregionalization - procedure for subdividing a geographic area into regions of relative homogeneity in ecological systems or in relationship between organisms and their environment.
Reservoir:A pond, lake, tank or basin, natural or man-made, used for the storage, regulation and control of water.
Riffle:A rocky shoal or sandbar lying just below the surface of a waterway. The choppy water created by such sand bars and shoals is also referred to as a riffle.
Riparian Rights:Entitlement of a land owner to certain uses of water on or bordering his property, including the right to prevent diversion or misuse of upstream waters. Generally a matter of state law.
Rough Fish:Those fish species considered to be of poor fighting quality when taken on tackle or of poor eating quality (gar, suckers, etc.). Most rough fish are more tolerant of widely changing environmental conditions than are game fish.
Runoff:The portion of rainfall, melted snow or irrigation water that flows across ground surface and eventually is returned to streams. Runoff can pick up pollutants from the air or the land and carry them to the receiving waters.
Salinity:The degree of salt in water.
Sedimentation:Letting solids settle out of wastewater by gravity during treatment.
SedimentationTanks:Wastewater tanks in which floating wastes are skimmed off and settled solids are removed for disposal.
Sediments:Soil, sand, and minerals washed from land into water, usually after rain. They pile up in reservoirs, rivers and harbors, destroying fish and wildlife habitat, and clouding the water so that sunlight cannot reach aquatic plants. Careless farming, mining, and building activities will expose sediment materials, allowing them to wash off the land after rainfall.
Sedges:Plants of the family Cyperacae that resemble grasses, but have solid stems
Seepage:Water that flows through the soil.
Sewage:The total of organic waste and waste water generated by residential and commercial establishments.
Silt:Finely divided particles of soil or rock. Often carried in cloudy suspension in water and eventually deposited as sediment.
Sole Source Aquifer:An aquifer that supplies 50percent or more of the drinking water of an area.
Species:A reproductively isolated aggregate of interbreeding organisms.
Spring Melt/Thaw:The process by which warm temperatures melt winter snow and ice. Because various forms of acid deposition may have been stored in the frozen water, the melt can result in abnormally large amounts of acidity entering streams and rivers, sometimes causing fish kills.
Stratification:Separating into layers.
Streambed:The channel through which a natural stream or river runs or once ran through.
Stressors- physical and biological factors that adversely affect aquatic organisms.
Surface Runoff:Precipitation, snow melt, or irrigation in excess of what can infiltrate the soil surface and be stored in small surface depressions; a major transporter of nonpoint source pollutants.
Surface Water:All water naturally open to the atmosphere (rivers, lakes, reservoirs, ponds, streams, impoundments, seas, estuaries, etc.) and all springs, wells, or other collectors directly influenced by surface water.
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.
Taxa- a grouping of organisms given a formal taxonomic name such as species, genus, family, etc.
Tillage:Plowing, seedbed preparation, and cultivation practices.
Topography:The physical features of a surface area including relative elevations and the position of natural and man-made features.
Total Maximum Daily Loads (TMDLs) - 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 source.
Total Suspended Particles:A method of monitoring particulate matter by total weight.
Total Suspended Solids (TSS):A measure of the suspended solids in wastewater, effluent, or water bodies, determined by tests for total suspended nonfilterable solids.(See: suspended solids.)
Toxicity:The quality or degree of being poisonous or harmful to plant or animal life.
Toxic Pollutants:Materials that cause death, disease, or birth defects in organisms that ingest or absorb them. The quantities and exposures necessary to cause these effects can vary widely.
Transpiration:The loss of water vapor by plants through tiny holes in their leaves called stomata. According to Environment Canada, an actively growing plant may transpire as much as ten times the amount of water it can hold at once within a twenty-four hour period.
Tributary:A stream or other body of water, surface or underground, which intermittently contributes its water in small quantities to another larger stream or body of water.
Trophic Status:Available phosphate content and subsequent biological productivity.
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.
Use Attainability Analysis (UAA) - analysis that describes factors limiting designated use of waterbodies.
Waste Water:Water carrying wastes from homes, businesses and industries that is a mixture of water and dissolved or suspended solids.
Water Cycle:The process, also known as the hydrologic cycle, in which water travels in a sequence from the air through condensation to the earth as precipitation and back to the atmosphere by evaporation.
Water Pollution:The addition of sewage, industrial wastes or other harmful or objectionable material to water in concentrations or in sufficient quantities to result in measurable degradation of water quality.
Water Quality-Based Limitations:Effluent limitations applied to dischargers when mere technology-based limitations would cause violations of water quality standards. Usually applied to discharges into small streams.
Water Quality-Based Permit:A permit with an effluent limit more stringent than one based on technology performance. Such limits may be necessary to protect the designated use of receiving waters (i.e., recreation, irrigation, industry or water supply).
Water Quality Criteria:Levels of water quality expected to render a body of water suitable for its designated use. Criteria are based on specific levels of pollutants that would make the water harmful if used for drinking, swimming, farming, fish production, or industrial processes.
Water Quality Standards:State-adopted and EPA-approved ambient standards for water bodies. The standards prescribe the use of the water body and establish the water quality criteria that must be met to protect designated uses.
Water Table:The level or depth below the ground that is saturated with water.
Water Vapor:Water diffused as a gas in the atmosphere.
Watershed:The area of land from which rainfall (and/or snow melt) drains into a stream or other water body. Watersheds are also sometimes referred to as drainage basins or drainage areas. Ridges of higher ground generally form the boundaries between watersheds. At these boundaries, rain falling on one side flows toward the low point of one watershed, while rain falling on the other side of the boundary flows toward the low point of a different watershed.
Wellhead Protection Area:A protected surface and subsurface zone surrounding a well or well field supplying a public water system to keep contaminants from reaching the well water.
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.
Zooplankton:Tiny, sometimes microscopic, floating, aquatic animals. Zooplankton generally feed upon phytoplankton and each other.