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[A] [B] [C] [D] [E] [F] [G] [H] [I] [J] [K] [L] [M] [N] [O] [P] [Q] [R] [S] [T] [U] [V] [W] [X] [Y] [Z]
-A- Acclimation - response by an animal that enables it to tolerate a change in a single factor (e.g. temperature) in its environment. Address geocoding – assigning x, y coordinates to tabular data such as street addresses. Anadromous: Fish that return from salt water to fresh water to spawn (e.g., American shad, striped bass, etc.). 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 Insect: Insect species whose larval and/or juvenile forms live in the water. Anthropogenic - Man-made; arising from human activities. Attribute - a measurable component of a biological system. -B- Benthic macroinvertebrates: Aquatic larval stages of insects, such as dragonfly larvae and aquatic beetles; crustaceans such as crayfish; worms; and mollusks. These small creatures live throughout the stream bed attached to rocks, vegetation, and logs and sticks or burrowed into stream bottoms. Bioassessment: is an evaluation of the condition of a waterbody using biological surveys and other direct measurements of the resident biota (i.e., fish, macroinvertebrates, periphyton). Biological assemblages: Key groups of animals and plants -- such as benthic macroinvertebrates, fish, or algae -- that are studied to learn more about the condition of water resources. 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 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). -C-
Clarity: The clearness of the water in the stream. 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. Community - all the groups of organisms living together in the same area, usually interacting or depending on each other for existence. Cover: Overhanging or instream structures (such as tree roots, undercut streambanks, or boulders) that offer protection from predators, shelter from strong currents, and/or shading. Current: The velocity (speed) of the flow of water. -D-
-E- Ecological Integrity - The condition of an unimpaired ecosystem as measured by combined checmical, physical (including physical habitat), and biological attributes. Ecoregions: Ecological regions that are similar in climate, vegetation, soil type, and geology; water resources within a particular ecoregion have similar natural characteristics and similar responses to stressors. Ecosystem: The interacting system of a biological community (plants, animals) and its non-living environment. environmental technology – an all-inclusive term used to describe pollution control devices and systems, waste treatment processes and storage facilities, and site remediation technologies and their components that may be utilized to remove pollutants or contaminants from or prevent them from entering the environment. Examples include wet scrubbers (air), soil washing (soil), granulated activated carbon unit (water), and filtration (air, water). Usually, this term applies to hardware based systems; however, it also applies to methods or techniques used for pollution prevention, pollutant reduction, or containment of contamination to prevent further movement of the contaminants, such as capping, solidification or vitrification, and biological treatment. Erosion: The wearing away of the land surface by wind or water. -F- feature – an entity in a spatial data layer, such as a point, line, or polygon, that represents a geographic object. Federal Geographic Data Committee – the Federal Geographic Data Committee (FGDC) coordinates the development of the National Spatial Data Infrastructure (NSDI). The NSDI encompasses policies, standards, and procedures for organizations to cooperatively produce and share geographic data. The 17 federal agencies that make up the FGDC are developing the NSDI in cooperation with organizations from state, local, and tribal governments, the academic community, and the private sector. -G- geographic information system (GIS): A collection of computer hardware, software, and geographic data designed to capture, store, update, manipulate, analyze, and display geographically referenced data. geospatial data – the information that identifies the geographic location and characteristics of natural or constructed features and boundaries on the earth. This information may be derived from, among other things, remote-sensing, mapping, and surveying technologies. Geomorphology: Stream Geomorphology is the study of landform evolution related to stream systems. As an integrative field it includes the related disciplines of geology, hydrology and hydraulics, sediment transport, soil mechanics, and the mechanical effects of vegetation. Global Positioning System (GPS) – a constellation of 24 satellites, developed by the U.S. department of Defense, that orbit the earth at an altitude of 20,200 kilometers. These satellites transmit signals that allow a GPS receiver anywhere on earth to calculate its own location. The global positioning system is used in navigation, mapping, surveying, and other applications where precise positioning is necessary. Gradient: The slope or steepness of the stream. -H- 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. -I- 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. 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. In-stream fish habitat: Areas fish need for concealment and feeding, such as large wood within the stream banks, boulders, undercut banks, and tree roots. -J- -K- -L- -M- 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). Macroinvertebrate Index of Biotic Condition: The sum of a number of individual measures of biological condition, such as the number of taxa in a sample, the number of taxa with different habits and feeding strategies, etc. map projection – a mathematical formula or algorithm for translating the coordinates of features on the surface of the earth to a plane for representation on a flat map. map resolution – the accuracy with which the location and shape of map features are depicted for a given map scale. map scale – a statement of a measure on the map and the equivalent measure on the earth, often expressed as a representative fraction of distance, such as 1:24,000. map, thematic – map designed to provide information on a single topic, such as geology, rainfall, or population. metadata – information about a data set. Metadata for geographical data may include the source of the data; its creation date and format; its projection, scale, resolution, and accuracy; and its reliability with regard to some standard. 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. Modified Index of Biotic Integrity (mIBI): This analysis consists of six total metrics that are used to determine watershed biotic integrity across broad spatial scales. For more information on mIBI, please click here.Monitor: To measure a characteristic, such as streambank condition, dissolved oxygen, or fish population, using uniform methods to evaluate change over a period of time. Multivariate Community Analysis - statistical methods (e.g. ordination or discriminant analysis) for analyzing physical and biological community data using multiple variables. -N- National Hydrography Dataset: Comprehensive set of digital spatial data -- based on U.S. Geological Survey 1:100,000 scale topographic maps -- that contains information on surface water features such as streams, rivers, lakes and ponds. Nonpoint Source Pollution: “Diffuse” pollution, generated from large areas with no particular point of pollutant origin, but rather from many individual places. Urban and agricultural areas generate nonpoint source pollutants. Nutrients: Substances such as nitrogen and phosphorus that can over-stimulate the growth of algae and other plants in water. Nutrients in streams and lakes can come from agricultural and urban runoff, leaking septic systems, sewage discharges and similar sources. -O- O/E (Observed/Expected) Ratio of Taxa Loss: A ratio comparing the number of taxa expected (E) to exist at a site to the number that are actually observed (O). The taxa expected at individual sites are based on models developed from data collected at reference sites. orthophotography – perspective aerial photography from which distortions owing to camera tilt and ground relief have been removed. Orthophotography has the same scale throughout and can be used as a map. -P- Perennial streams: Flowing throughout the year. Point Source Pollution: A discharge of water pollution to a stream or other body of water, via an identifiable pipe, vent, or culvert. Pool: An area of relatively deep slow water in a stream that offers shelter to fish. Probability-based design: A type of random sampling technique in which every element of the population has a known probability of being selected for sampling. -Q- Quality Control (QC): The system of checks that are used to generate excellence, or quality, in a program (a monitoring program, for example). QC asks if we are doing things right. Quality Assurance (QA): Quality Assurance is a way to see that QC is maintained and is we are monitoring the right things to detect changes in water quality. -R- Reach: Stream segment. Reference condition: The least-disturbed condition available in an ecological region, determined based on specific criteria, used as a benchmark for comparison with sampled sites in the 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. Riffle: A shallow, gravelly area of streambed with swift current. Used for spawning by salmonids and other fishes. Riprap: A sustaining wall built of rocks. Riparian disturbance: A measure of the evidence of human activities in and alongside streams, such as dams, roadways, pastureland, and trash. Riparian vegetative cover: Vegetation corridor alongside streams and rivers. Intact riparian vegetative cover reduces pollution runoff, prevents streambank erosion, and provides shade, lower temperatures, food, and habitat for fish and other aquatic organisms. -S- scale – relationship existing between a distance on a map, chart, or photograph and the corresponding distance on the earth. Sediment: Fine soil or mineral particles that settle to the bottom of the water or are suspended in it. Stream order: Stream size, based on the confluence of one stream with another. 1st order streams are the origin or headwaters. The confluence or joining of two 1st order streams forms a second order stream, the confluence of two 2nd order streams forms a 3rd order stream, and so on. Streambed sediments: Fine sediments and silt on the streambed. In excess quantities, they can fill in the habitat spaces between stream cobbles and boulders, and suffocate macroinvertebrates and fish eggs. Stressors: Effects or substances that are stressful to -- and therefore degrade -- aquatic ecosystems. Stressors may be chemical (e.g., nutrients), physical (e.g. excess sediments on the streambed), or biological (e.g., competing invasive species). Substrate: The material that makes up the bottom layer of the stream, such as gravel, sand, or bedrock. Stream Corridor: The lower and upperbanks of a perennial or intermittent stream.
Suspended Sediments: Fine material or soil particles that remain suspended by the current until deposited in areas of weaker current. They create turbidity and, when deposited, can smother fish eggs or alevins. Can be measured in a laboratory as “Total Suspended Solids” (TSS). -T- Taxa: Plural of taxon; groupings of living organisms, such as phylum, order, family, genus, or species. Scientists organize organisms into taxa in order to better identify and understand them. topography – configuration (relief) of the land surface; the graphic delineation or portrayal of that configuration in map form, as by contour lines. In oceanography the term is applied to a surface such as the sea bottom or surface of given characteristics within the water mass. 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. -U- -V- vector – a data structure used to represent linear geographic features. Features are made of ordered lists of x, y coordinates and represented by points, line, or polygons; points connect to become lines, and lines connect to become polygons. Attributes are associated with each feature. Virtual Stream Score: A Virtual Stream Score (VSS) is a percent comparability score of a particular biological to a reference condition. The reference condition is acutally a model of what a 'model' reference site would look like biologically. Because all bioassessments need a reference condition and there are very few 'non-impacted' streams in Virginia, VCU created a model reference site for stream fishes, macroinvertebrates, and a conbination of both. -W- Wadeable streams: Streams that are small and shallow enough to adequately sample by wading, without a boat. Wetlands: Wetlands are lands where saturation with water is the dominant factor determining the nature of soil development. They also can be identified by unique plants which have adapted to oxygen-deficient (anaerobic) soils. Wetlands influence stream flows and water quality. -X- -Y- -Z- Zoning: To designate, by ordinances, areas of land reserved and regulated for specific uses, such as residential, industrial, or open space. |
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| This document was last updated on
November 7, 2008
Virginia Commonwealth University Center for Environmental Studies 1000 West Cary Street - Richmond, Virginia 23284 - 804-828-7202 (Phone) - 804-828-1622 (fax) - Contact the INSTAR team |
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Stream Mouth: The place where a stream empties into a lake, ocean, or another stream.