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Glossary

Afterbay
A lake or water impoundment located downstream from the powerplant that receives the water after it has passed through the hydroelectric turbines.
Agriculture water use
Composed of livestock, animal specialty, and irrigation water use.
Animal Specialties water use
Water use associated with the production of fur-bearing animals in captivity, horses, rabbits, and pets. Establishments engaged in the hatching or production of finfish and shellfish are classified as an aquaculture water use. See also aquaculture and livestock water use.
Aquaculture
Farming of organisms that live in water, such as fish, shellfish, and algae within a confined space and under controlled feeding, sanitation, and harvesting procedures. Establishments primarily engaged in hatching fish and in operating fishing preserves. See also fish farms and fish hatcheries.
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.
Blowdown
The continuous or intermittent discharge, or purging, of a small amount of circulating water, normally expressed as a percentage of the water being circulated. Its purpose is to prevent an increase in the concentration of solids in the water due to evaporation.
Capacity
Is a volume when referring to a cooling tower. It is the average amount of water circulating in the cooling system at any given time, expressed in gallons per minute. This is not the production capacity of the power generation plant.
Commercial water use
Water used for motels, hotels, restaurants, office buildings, other commercial facilities, and institutions. The water may be obtained from a public supply or may be self supplied. See also public supply and self-supplied water.
Consumptive use
That part of water withdrawn that is evaporated, transpired, incorporated into products or crops, consumed by humans or livestock, or otherwise removed from the immediate water environment. Also referred to as water consumed.
Conveyance loss
Water that is lost in transit from a pipe, canal, conduit, or ditch by leakage or evaporation. Generally, the water is not available for use; however, leakage from an irrigation ditch, for example, may percolate to a ground-water source and be available for further use.
Cooling water
Water used for cooling purposes, such as of condensers and nuclear reactors.
Delivery/release
The amount of water delivered to the point of use and the amount released after use; the difference between these amounts is usually the same as the consumptive use. See also consumptive use.
Desalination
Refers to the removal of salts from water. Desalination is primarily used to produce public-supply water that meets drinking water standards. The primary types of desalination are: distillation, electrodialysis, and reverse osmosis. Additionally, many public suppliers also dilute or blend saltwater with fresher water to produce potable water.
Dewatering
(1) The draining, pumping, or removal of water that is affecting construction or mining site, or to lower the water table for agriculture. (2) The removal of water from a substance (sewage or waste screenings, for example).
Domestic water use
Water for household purposes, such as drinking, food preparation, bathing, washing clothes and dishes, flushing toilets, and watering lawns and gardens. Also called residential water use. The water may be obtained from a public supply or may be self- supplied. See also public supply and self-supplied water.
Drift
The fine water droplets blown out of a cooling tower with the exhaust air, expressed as a percentage of water circulated. Drift loss can be held to 0.2 percent of the circulating water (Weisman, 1985).
Evaporation
Process by which water is changed from a liquid into a vapor. See also evapotranspiration and transpiration.
Evapotranspiration
A collective term that includes water discharged to the atmosphere as a result of evaporation from the soil and surface-water bodies and as a result of plant transpiration. See also evaporation and transpiration.
Fish farm water use
Water used for the production of finfish and shellfish under controlled feeding, sanitation, and harvesting procedures for sale or market consumption. Water use by fish farms is classified in the aquaculture category. See also aquaculture and fish hatcheries.
Fish hatchery water use
Water used for raising fish for later release, used in associated with the operation of fish hatcheries or fishing preserves. Fish hatchery water use is classified in the aquaculture category. See also aquaculture and fish farms.
Forebay
A lake or water impoundment (reservoir) located at the end of a diversion canal or conduit and before the entrance to the powerplant.
Freshwater
Water that contains less than 1,000 mg/L of dissolved solids; generally, more than 500 mg/L of dissolved solids is undesirable for drinking and many industrial uses.
Geothermal power water use
The use of water in the generation of electricity at plants where the energy is extracted from water that is heated by the internal heat of the earth.
Gigawatt-hour (GWh)
A unit of energy equivalent to one billion watt-hours.
Ground water
Generally all subsurface water as distinct from surface water; specifically, that part of the subsurface water in the saturated zone (a zone in which all voids are filled with water).
Hydroelectric power water use
The use of water in the generation of electricity at plants where the turbine generators are driven by falling water.
In-channel use
See instream use.
Industrial water use
Water used for industrial purposes such as fabrication, processing, washing, and cooling, and includes such industries as steel, chemical and allied products, paper and allied products, smelting, and petroleum refining. The water may be obtained from a pubic supply or may be self supplied. See also public supply and self-supplied water.
Instream use
Water that is used from a surface-water source for such purposes as hydroelectric power generation, navigation, water-quality improvement, fish propagation, and recreation. Sometimes called nonwithdrawal use or in-channel use.
Irrigation district
A cooperative, self-governing public corporation set up as a subdivision of the State government, with definite geographic boundaries, organized and having taxing power to obtain and distribute water for irrigation of lands within the district; created under the authority of a State legislature with the consent of a designated fraction of the landowners or citizens.
Irrigation system [irrigation]
Practices and equipment used in providing and distributing water to the land/crop being irrigated. Main systems and some associated terms are listed (technological advances are ongoing to reduce cost and improve efficiencies:
Alternate set irrigation
A method of managing irrigation whereby, at every other irrigation, alternate furrows are irrigated, or sprinklers are placed midway between their locations during the previous irrigation.
Alternate side irrigation
The practice of furrow irrigating one of a crop row (for row crops or orchards) and then, at about half the irrigation time, irrigating the other side.
Basin irrigation
Irrigation by flooding area of level land surrounded by dikes. Used interchangeable with level border irrigation, but usually refers to smaller areas.
Border dike
Earth ridge or small levee built to guide or to hold irrigation or recharge water in a field.
Border ditch
Small excavation used as a border of an irrigated strip or plot with water being spread from one or both sides.
Border irrigation
Irrigation by flooding strips of land, rectangular in shape and cross leveled, bordered by dikes. Water is applied at a rate sufficient to move it down the strip in a uniform sheet. Border strips having no downfield slope are referred to as level order systems. Border systems constructed on terraced land are commonly referred to as benched borders.
Check irrigation
Modification of a border strip with small earth ridges or checks constructed at intervals to retain water as the water flows down the strip (ASAE).
Continuous-flow irrigation
System of irrigation water delivery where each irrigator receives the allotted quantity of water continuously (ASAE).
Demand irrigation system
Irrigation water delivery procedure where each irrigator may request water in the amount needed and at the time desired (ASAE).
Drip irrigation
A method of microirrigation wherein water is applied to the soil surface as drops or small streams through emitters. Discharge rates are generally less than 8 L/h (2 gal/hr) for single-outlet emitters and 12 L/hr (3 gal/hr) per meter for line-source emitters.
Effluent irrigation
Land application of wastewater for irrigation and beneficial use of nutrients.
Emitter types
Small microirrigation dispensing devices designed to dissipate pressure and discharge a small uniform flow or trickle of water at a constant discharge, which does not vary significantly because of minor differences in pressure head. Also called "dripper" or "trickler".
Compensating emitter
Designed to discharge water at a constant rate of a wide range of later line pressures.
Continuous flushing emitter
Designed to continuously permit passage of large solid particles while operating at a trickle or drip flow thus reducing filter fineness requirements.
Flushing emitter
Designed to have a flushing flow of water to clear the discharge opening every time the system is turned on.
Line-source emitter
Water is discharged from closely spaced perforations, emitters, or a porous wall along the tubing.
Long path emitter
Employs a long capillary-sized tube or channel to dissipate pressure.
Multi-outlet emitter
Supplies water to 2 or more points through small diameter auxiliary tubing.
Orifice emitter
Employs a series of orifices to dissipate pressure.
Vortex emitter
Employs a vortex effect to dissipate pressure.
Flood irrigation
Method of irrigation where water is applied to the soil surface without flow controls, such as furrows, borders, or corrugations.
Full irrigation
Management of water application to fully replace the soil water deficiency over an entire field.
Furrow
Small channel in the soil surface for conveying irrigation water.
Furrow irrigation
Method of surface irrigation where the water is supplied to small ditches or furrows for guiding across the field.
Gated pipe irrigation
Portable pipe with small gates installed along one side for distributing water to corrugations or furrows.
Irrigation stream
Flow for irrigation of a particular tract of land. Flow or water distributed at a single irrigation. Sometimes called "irrigating head".
Irrigation check
Small dike or dam used in the furrow alongside an irrigation border to make the water spread evenly across the border.
Irrigation interval
The average time interval between the commencement of successive irrigations for a given field. Sometimes called irrigation frequency.
Irrigation set
The area irrigated at one time within a field.
Limited irrigation
Management of irrigation applications to apply less than enough water to satisfy the soil water deficiency in the entire root zone. Sometimes called "deficit" or "stress" irrigation.
Microirrigation
The frequent application of small quantities of water as drops, tiny streams, or miniature spray through emitters or applicators placed along a water delivery line. Microirrigation encompasses a number of methods or concepts such as bubbler, drip, trickle, mist, or spray.
Mist irrigation
A method of microirrigation in which water is applied in very small droplets.
Normal Capacity
The volume in a reservoir below the normal retention level, including dead storage, but excluding flood control or surcharge storage.
Overhead irrigation
(See Sprinkler Irrigation).
Porous trickle tubing
(Microirrigation) Tubing with a uniformly porous wall. The pores are small and ooze water under pressure.
Portable pipe
Irrigation system that is or can be moved between irrigation sets, such as sprinkler or gated pipe.
Preplant irrigation
Irrigation applied prior to seeding. Sometimes called preirrigation.
Spray irrigation
The application of water by a small spray or mist to the soil surface, where travel through the air becomes instrumental in the distribution of water.
Sprinkler irrigation
Method of irrigation in which the water is sprayed, or sprinkled, through the air to the ground surface.
Sprinkler irrigation systems:
Boom
An elevated, cantilevered sprinkler(s) mounted on a central stand. The sprinkler boom rotates about a central pivot.
Center pivot
An automated irrigation system consisting of a sprinkler line rotating about a pivot point at one end and supported by a number of self-propelled towers. The water is supplied at the pivot point and flows outward through the line supplying the individual outlets.
Corner pivot
An additional span or other equipment attached to the outer end of a center pivot irrigation system that allows the overall radius to increase or decrease in relation to the field boundaries.
Lateral move
An automated irrigation machine consisting of a sprinkler line supported by a number of self-propelled towers. The entire unit moves in a generally straight path and irrigates a basically rectangular area. Sometimes called a "linear move".
Permanent
Underground piping with risers and sprinklers.
Portable (hand move)
Sprinkler system which is moved by uncoupling and relocating the pipes manually, requiring no special tools.
Side move sprinkler
A sprinkler system with the supply pipe supported on carriages and towing small diameter tailing pipelines, each fitted with several sprinkler heads.
Side-roll sprinkler
The supply pipe is usually mounted on wheels with the pipe as the axle and where the system is moved across the field by rotating the pipelines by engine power.
Solid set
System which covers the complete field with pipes and sprinklers in such a manner that all the field can be irrigated without moving any of the system.
Towed sprinkler
System where lateral lines are mounted on wheels, sleds, or skids, and are pulled or towed in a direction approximately parallel to the lateral.
Stress irrigation
Management of irrigation water to apply less than enough water to satisfy the soil water deficiency in the entire root zone. (Preferred term is Limited irrigation.).
Sub irrigation
Application of irrigation water below the ground surface by raising the water table to within or near the root zone.
Subsurface drip irrigation
Application of water below the soil surface through emitters, with discharge rates generally in the same ranges as drip irrigation. This method of application is different from and not to be confused with sub irrigation, where the root zone is irrigated by water table control.
Surface irrigation
Broad class of irrigation methods in which water is distributed over the soil surface by gravity flow.
Surge irrigation
A surface irrigation technique wherein flow is applied to furrows (or less commonly, borders) intermittently during a single irrigation set.
Trickle irrigation
A method of microirrigation wherein water is applied to the soil surface as drops or small streams through emitters. (Preferred term is Drip irrigation.
Water spreading
A specialized form of surface irrigation accomplished by diverting flood runoff from natural channels or watercourses and spreading the flow over relatively level areas.
Irrigation water use
Artificial application of water on lands to assist in the growing of crops and pastures or to maintain vegetative growth in recreational lands such as parks and golf courses. Also includes irrigation for cemeteries, turf farms and other landscaped areas, not including domestic lawns and gardens (which are included in "domestic water use" definition).
Kilowatt-hour (kWh)
A unit of energy equivalent to one thousand watt-hours.
Livestock water use
Water for livestock watering, feedlots, dairy operations, and other on-farm needs. Livestock as used here includes cattle, sheep, goats, hogs, poultry, horses, and animal specialties. See also rural water use and animal specialties.
Makeup
The water pumped into the system to replace the circulating water lost by evaporation, drift, blowdown and leakage; expressed as a percentage of the water circulated.
Mining water use
Water use for the extraction of minerals occurring naturally including solids, such as coal and ores; liquids, such as crude petroleum; and gases, such as natural gas. Also includes uses associated with quarrying, well operations (dewatering), milling (crushing, screening, washing, floatation, and so forth), and other preparations customarily done at the mine site or as part of mining activity. Does not include water used in processing, such as smelting, refining petroleum, or slurry pipeline operations; these uses are included in industrial water use.
Non-account water
The difference between public-supply withdrawals and deliveries. Also known as public-supply residual or public use and loss.
Offstream use
Water withdrawn or diverted from a surface-water source for public-water supply, industry, irrigation, livestock, thermoelectric power generation, and other uses. Sometimes called off-channel use or withdrawal.
Per capita water use
The average amount of water used per person during a standard time period, generally per day.
Precipitation
The liquid equivalent (depth) of rainfall, snow, sleet, or hail. The data that is used is more correctly referred to as "Observed Precipitation" and in all cases is somewhat less than actual due to the imperfectness of measuring devices.
Preirrigation
The application of water to cropland before planting to assure adequate crop germination and early plant growth.
Public supply
Water withdrawn by public and private water suppliers and delivered to users. Public suppliers provide water for a variety of uses, such as domestic, commercial, thermoelectric power, industrial, and public water use. See also commercial water use, domestic water use, thermoelectric power water use, industrial water use, and public water use.
Public-supply deliveries
Water provided to users through a public-supply distribution system.
Pumped storage
Storage in an afterbay that is pumped back to the forebay above the powerplant at a time when customer demand for energy is low, such as at night. Pumped storage is a method of keeping water in reserve for use during peak period power demands. In some cases, the forebay may be located offstream.
Public water use
Water supplied from a public-water supply and used for such purposes as firefighting, street washing, and municipal parks and swimming pools. See also public supply.
Reclaimed wastewater
Wastewater treatment plant effluent that has been diverted for beneficial use before it reaches a natural waterway or aquifer.
Recycled water
Water that is used more than one time before it passes back into the natural hydrologic system.
Residential water use
See domestic water use.
Return flow
The water that reaches a ground-water or surface-water source after release from the point of use and thus becomes available for further use.
Reuse
Use of water that has undergone wastewater treatment and is delivered to a user as reclaimed wastewater. Seealso recycled water.
Rural water use
A term used in previous water-use circulars to describe water used in suburban or farm areas for domestic and livestock needs. The water generally is self supplied, and includes domestic use, drinking water for livestock, and other uses, such as dairy sanitation, evaporation from stock watering ponds, and cleaning and waste disposal. See also domestic water use, livestock water use, and self-supplied water.
Saline water
Water that contains more than 1,000 milligrams per liter dissolved solids.
Self-supplied water
Water withdrawn from a surface-water or a ground-water source by a user and not obtained from a public supply.
Standard industrial classification (SIC) codes
Four-digit codes established by the Office of Management and Budget and used in the classification of establishments by type of activity in which they are engaged.
Surface-water
An open body of water, such as a stream or lake.
Thermoelectric power water use
Water used in the process of the generation of thermoelectric power. The water may be obtained from a public supply or may be obtained from a public supply or may be self supplied. See also public supply and self-supplied water.
Transpiration
Process by which water that is absorbed by plants, usually through the roots, is evaporated into the atmosphere from the plant surface. See also evaporation and evapotranspiration.
Wastewater
Water that carries wastes from homes, businesses, and industries.
Wastewater treatment
The processing of wastewater for the removal or reduction of contained solids or other undesirable constituents.
Wastewater-treatment return flow
Water returned to the hydrologic system by wastewater-treatment facilities.
Water use
(1) In a restrictive sense, the term refers to water that is actually used for a specific purpose, such as for domestic use, irrigation, or industrial processing. (2) More broadly, water use pertains to human's interaction with and influence on the hydrologic cycle, and includes elements such as water withdrawal, distribution, consumptive use, wastewater collection, and return flow.
Water-resources accounting unit
Many of the 222 designated water resources sub regions are divided into accounting units. These 352 hydrologic accounting units nest within or are equivalent to the planning sub regions. The U.S. Geological Survey uses the accounting units for designing and managing the National Water Data Network. See water-resources sub region.
Water-resources cataloging unit
Many of the 352 water-resources accounting units are divided into cataloging units. A cataloging unit is a geographic area representing part or all of a surface drainage basin, a combination of drainage basins, or a distinct hydrologic feature. The approximately 2,150 cataloging units in the Nation are used for cataloging and indexing water-data acquisition activities. See water-resources accounting unit.
Water-resources region
Designated natural drainage basin or hydrologic area that contains either the drainage area of a major river or the combined drainage areas of two or more rivers; of 21 regions, 18 are in the conterminous United States, and one each are in Alaska, Hawaii, and the Caribbean.
Water-resources sub region
The 21 designated water resources regions of the United States are subdivided into 222 sub regions. Each sub region includes that area drained by a river system, a reach of a river and its tributaries in that reach, a closed basin(s), or a group of streams forming a costal drainage system. See water-resources region.
Water transfer
Artificial conveyance of water from one area to another.
Water treatment
The processes that withdrawn water may undergo prior to use, including chlorination, fluoridation, and filtration.
Water use
(1) In a restrictive sense, the term refers to water that is actually used for a specific purpose, such as for domestic use, irrigation, or industrial processing. In this report, the quantity of water use for a specific category is the combination of self-supplied withdrawals and public-supply deliveries. (2) More broadly, water use pertains to human's interaction with and influence on the hydrologic cycle, and includes elements such as water withdrawal, delivery, consumptive use, wastewater release, reclaimed wastewater, return flow, and instream use. See also offstream and instream use.
Watt-hour (Wh)
An electrical energy unit of measure equal to one watt of power supplied to, or taken from, an electrical circuit steadily for one hour.
Withdrawal
The removal of surface water or ground water from the natural hydrologic system for use, including public-water supply, industry, commercial, domestic, irrigation, livestock, thermoelectric power generation, water uses.

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