Water Glossary - A
Abandoned water right: A water right which was not put to beneficial use for a number of years, generally five to seven years.
Abandoned well: A well which is no longer used. In many places, abandoned wells must be filled with cement or concrete grout to prevent pollution of ground water bodies.
Absolute: The micron rating of a filter. It indicates that any particle larger than a specific size will be trapped within the filter.
Absorb: To take in.
Absorption: When a solid takes up molecules into its structure.
Accretion: A gradual increase in land area adjacent to a river
Acid aerosol: Very small liquid or solid particles that are acidic and are small enough to become airborne.
Acid mine drainage: Low pH drainage water from certain mines usually caused by the oxidation of sulfides to sulfuric acid. Mine drainage can also contain high concentration of metal ions.
Acid rain: Rainfall with a pH of less than 7.0. One source is the combining of rain and sulfur dioxide emissions, which are a by-product of combustion of fossil fuels. Also referred to as acid deposition and wet deposition.
Acidity: The quantitative capacity of water to neutralize a base, expressed in ppm or mg/L calcium carbonate equivalent. The number of hydrogen atoms that are present determines this. It is usually measured by titration with a standard solution of sodium hydroxide.
Acre-foot (acre-ft): The volume of water required to cover 1 acre of land (43,560 square feet) to a depth of 1 foot.
Activated carbon adsorption: The process of pollutants moving out of water and attaching on to activated carbon.
Activated sludge: Oxygen dependent biological process that serves to convert soluble organic matter to solid biomass, that is removable by gravity or filtration.
Active groups: Really fixed ions bolted on to the matrix of an ion exchanger. Each active group must always have a counter-ion of opposite charge near itself.
Adhesion: The molecular attraction asserted between the surfaces of bodies in contact. Compare cohesion.
Adjudication: A court proceeding to determine all rights to the use of water on a particular stream system or ground water basin.
Adsorption: The adhesion of a substance to the surface of a solid or liquid. Adsorption is often used to extract pollutants by causing them to be attached to such adsorbents as activated carbon or silica gel. Hydrophobic, or water-repulsing adsorbents, are used to extract oil from waterways in oil spills.
Advanced oxidation process: One of several combination oxidation processes. Advanced chemical oxidation processes use (chemical) oxidants to reduce COD/BOD levels, and to remove both organic and oxidisable inorganic components. The processes can completely oxidize organic materials to carbon dioxide and water, although it is often not necessary to operate the processes to this level of treatment.
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. This treatment is more stringent than secondary treatment, and requires an 85 percent reduction in conventional pollutant concentrations or a significant reduction in non-conventional pollutants.
Aerated lagoon: A water treatment pond that speeds up biological decomposition of organic waste by stimulating the growth and activity of bacteria, which are responsible for the degradation.
Aeration: The mixing or turbulent exposure of water to air and oxygen to dissipate volatile contaminants and other pollutants into the air
Aeration tank: A tank that is used to inject air into water.
Aerobic: A process that takes place in the presence of oxygen, such as the digestion of organic matter by bacteria in an oxidation pond.
Aerosol: Very small liquid or solid particles dispersed in air.
Affinity: The keenness with which an ion exchanger takes up and holds on to a counter-ion. Affinities are very much affected by the concentration of the electrolyte surrounding the ion exchanger.
Agglomeration: A process of bringing smaller particles together to form a larger mass.
Aggressive water: Water which is soft and acidic and can corrode plumbing, piping, and appliances
Agricultural irrigation: Water distribution systems and practices in agriculture.
Agriculture water use: Includes water used for agricultural irrigation and nonirrigation purposes. Irrigation water use includes the artificial application of water on lands to assist in the growing of crops, plants, and pasture, or to maintain vegetative growth in recreational lands, parks, and golf courses. Nonirrigation water use includes water used for livestock, fish farming, and other farm needs. Livestock water use includes water used for stock watering, feedlots, and dairy operations.
Air heat exchange: Cooling method, involving no water loss, during which a fan blows air past finned tubes carrying recirculating cooling water.
Algae: Simple rootless plants that grow in sunlit waters in relative proportion to the amounts of nutrients available. They can affect water quality adversely by lowering the dissolved oxygen in the water. They are food for fish and small aquatic animals.
Algae blooms: Rapid growth of algae on the surface of lakes, streams, or ponds; stimulated by nutrient enrichment.
Aliquot: A measured portion of a sample taken for analysis. One or more aliquots make up a sample.
Alkali: Any strongly basic substance of hydroxide and carbonate, such as soda, potash, etc., that is soluble in water and increases the pH of a solution.
Alkalinity: The measurement of constituents in a water supply which determine alkaline conditions. The alkalinity of water is a measure of its capacity to neutralize acids. See pH.
Alluvium: Sediments deposited by erosion processes, usually by streams.
Alvusion: A sudden or perceptible change in a river's margin, such as a change in course or loss of banks due to flooding.
Anaerobic: A process that takes place in the absence of oxygen, such as the digestion of organic matter by bacteria in a UASB-reactor.
Animal specialties: Water use associated with the production of fish in captivity except fish hatcheries, fur-bearing animals in captivity, horses, rabbits, and pets. See also livestock water use.
Anion: A negatively charged ion that results from the dissociation of salts, acids or alkali's in solution.
Annular space: The space between two concentric cylindrical objects, one of which surrounds the other, such as the space between the walls of a drilled hole and a casing.
Aquaculture: Farming of organisms that live in water, such as fish, shellfish, and algae.
Aquatic: Growing in, living in, or frequenting water
Aquatic ecosystem: Basic ecological unit composed of living and nonliving elements interacting in an aqueous milieu.
Aqueous: Something made up of water.
Aqueous solubility: The maximum concentration of a chemical that dissolves in a given amount of water.
Aquiclude: A formation which, although porous and capable of absorbing water slowly, will not transmit water fast enough to furnish an appreciable supply for a well or a spring.
Aquiculture: The raising or fattening of fish in enclosed ponds. Compare mariculture.
Aquifer: A geologic formation, group of formations, or part of a formation that contains sufficient saturated permeable material to yield significant quantities of water to wells and springs.
Arid: Describes regions where precipitation is insufficient in quantity for most crops and where agriculture is impractical without irrigation.
Aromatics: A type of hydrocarbon that contains a ring structure, such as benzene and toluene. They can be found for instance in gasoline.
Artesian aquifer: A geologic formation in which water is under sufficient hydrostatic pressure to be discharged to the surface without pumping.
Artesian well: A water well drilled into a confined aquifer where enough hydraulic pressure exists for the water to flow to the surface without pumping.
Artesian zone: A zone where water is confined in an aquifer under pressure so that the water will rise in the well casing or drilled hole above the bottom of the confining layer overlying the aquifer.
Assimilation: The ability of water to purify itself of pollutants.
Assimilative capacity: The capacity of natural water to receive wastewaters or toxic materials without negative effects and without damage to aquatic life or humans who consume the water.
Atmosphere: The layer of gases surrounding the earth and composed of considerable amounts of nitrogen, hydrogen, and oxygen.
Atmospheric water: Water present in the atmosphere either as a solid (snow, hail), liquid (rain) or gas (fog, mist).
Attenuation: The process of reduction of a compound's concentration over time. This can be through absorption, adsorption, degradation, dilution or transformation.
Attrition: The action of one particle rubbing against the other in a filter media or ion exchange bed that can in time cause breakdown of the particles.
Available chlorine: A measure of the amount of chlorine available in chlorinated lime, hypochlorite compounds, and other materials.
Average annual recharge: Amount of water entering the aquifer on an average annual basis. Averages mean very little for the edwards because the climate of the region and structure of the aquifer produce a situation in which the area is usually water rich or water poor.