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GLOSSARY OF TERMS

There are a multitude of scientific, technical and legal terms that relate in some manner to water and water assets and hydrology.  The most comprehensive multilingual glossary of terms on the internet is found at the following link.

http://www.cig.ensmp.fr/~hubert/glu/aglo.htm

We have assembled a shorter list of terms that we think will cover most inquiries.

A B C D E F G H I J K L M N O P Q R S T U V W XYZ  

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aboriginal water right 
A water right used since time immemorial by aboriginal people such as sedentary Pueblo Indians.  The water rights are generally appurtenant only to arable lands that were or could be irrigated by gravity flow in ditches.
acre-foot 
A volume of water that covers one acre to a depth of one foot. Equivalent to 43,560 cubic feet or 325,829 US gallons. One acre-foot is equivalent to 1,233 cubic meters.
adjudicate 
To determine judicially. To settle by means of a court decision. 
adsorption
The process by which chemicals are held on the surface of a mineral or soil particle. 
air stripping 
A treatment process used to remove dissolved gases and volatile substances from water, accomplished by bubbling air through the water. 
alluvial 
Describes unconsolidated material such as sand, gravel, and silt which has been deposited by flowing water. 
appropriation
Appropriation of water requires an application to a regulatory agency, publication of notice of the intended appropriation, issuance of a permit, diversion of water to the place of use, and beneficial use.
appropriative rights 
Rights to or ownership of a supply of water which is appropriated, independent of land ownership, and put to beneficial use. Appropriative rights are allocated based on priority of use, and are subject to loss by non-use or abandonment. 
aquifer 
An underground formation of rock or sediment which is saturated and sufficiently permeable to transmit suitable quantities of water to a well or spring for the purpose intended.  One man's aquifer is another man's dry hole.
aquifer recharge 
Recharge to an aquifer where water from the surface percolates into a bed of rock that yields water in useable quantities.
artificial water 
Water produced by some works of man that is discharged into a watercourse and becomes available for use by the next downstream appropriator.  The user of artificial water has no right to require the producer of the water to continue the supply.

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beneficial use 
The concept of beneficial use requires actual use for some purpose that is socially accepted as "beneficial."    State ex rel. Martinez v. McDermott, 120 N.M. 327, 901 P.2d 745, 743 (Ct. App, 1995).  See also: Frank J. Trelease & George A. Gould, Water Law: Cases and Materials 32-38 (4th ed. 1986) (discussing the term "beneficial use"). In the arid American Southwest that was formerly under Spanish dominion, the concept derived from ancient Islamic law brought to Spain by the Al Moravid Confederation in the 11th Century.
best management practices
Techniques and practices that are accepted as the most effective and practical means to control pollutants or otherwise conserve water resources. 
bioremediation 
The utilization of living organisms such as bacteria to break down organic contaminants. 
BMPs 
See best management practices
bulk water
Water sold in tankers in bulk for delivery to bottling plants, municipalities, or industrial users.

 

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California Environmental Quality Act of 1970 
An act that requires public agency decision makers to consider the environmental impacts of a proposed plan. 
capital costs 
Costs of financing construction and equipment. Capital costs are usually fixed, one-time expenses. Compare operating and maintenance costs
carcinogen 
A substance which tends to produce cancer in a living organism.
catchment area of an aquifer
Area that comprises the intake area and all areas that contribute surface water to the intake area of aquifers.  The catchment area of an aquifer may or may not be have boundaries similar to the catchment area of a surface water stream.  When the surface water catchment area and the ground water catchment areas are dissimilar they are said to be disharmonious.
catchment area of surface water stream
Area that receive precipitation where the precipitation flows over the land surface and into rivulets, creeks, wadis, arroyos, and rivers.
 
CEQA 
See California Environmental Quality Act of 1970
CERCLA 
An Act of Congress, the Comprehensive Environmental Response, Compensation and Liability Act of 1980, which authorizes EPA to manage the cleanup of abandoned or uncontrolled hazardous waste sites. Also known as Superfund. 
chlorination 
The application of chlorine to water, generally for the purpose of disinfection. 
community water system 
A public water system which serves at least 15 service connections used by year-round residents or that regularly serves at least 25 year-round residents. Compare non-community water system
cone of depression 
The depression or drop in water level near a well, caused by the extraction of ground water from the well. 
confined aquifer 
An aquifer in which ground water is confined by an overlying impermeable or semi-permeable formation. Compare unconfined aquifer, semi-confined aquifer
conjunctive use 
A program that coordinates the storage of imported surface water supplies in local ground-water basins for future withdrawal and use. 
consumptive use 
A use of water in which water is removed from available supplies without direct return to a water resource system. 

consumptive irrigation requirement
The amount of water applied for irrigation of a crop that is taken up by the plant biomass and which is transpired by the plant and that evaporates.  The CIR is used consumptively and does not return to the hydrological system for further use.  The difference between the duty and the consumptive irrigation requirement is generally called "return flow."

contaminant

 
Any physical, chemical, biological, or radiological substance or matter that has an adverse effect on air, water, or soil.

correlative rights

Water rights where all users of water on an irrigation canal or an acequia have the same priority date of use and there is only one point of diversion for a common ditch or canal.

cubic meter

264 U.S. gallons or 219.82 Imperial gallons

cyclic storage 
Storage of supplemental water in a groundwater basin for subsequent recovery and use. 

 

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degradation 
Chemical or biological breakdown of a complex compound into simpler compounds. 
degrees of calcium carbonate concentration
Calcium carbonate concentration is commonly expressed as degrees.  However, the conversion from degrees depends on whose degrees you are using.
          German degree   = 17.9 ppm
American degree = 17.1 ppm
           English degree     = 14.3 ppm
French degree    = 10.0 ppm
denitrification 
The biochemical conversion of dissolved nitrate and nitrite nitrogen in soil or water to nitrogen gas. 
desalination 
The removal of dissolved salts, such as sodium chloride, from water. 
diffusion 
The movement of suspended or dissolved particles from an area of higher concentration to an area of lower concentration as the result of random movement of individual particles. 
disharmonious catchment areas
catchment areas for surface water and ground water that are no co-linear such that the geographic boundaries of the respective catchment areas differ.
drainage basin
A part of the surface of the lithosphere that is occupied by a drainage system or contributes water to a master stream.  Drainage basisns of master streams may contain many minor drainage basins.
drainage divide
The rim of a catchment area and the divide between adjacent catchment areas.
drawdown 
The measured drop in water level in or near a well caused by pumping groundwater from the well. 
duty
Duty is the total amount of water that is used for irrigation.  It is usually expressed as acre feet per acre or cubic meters per hectare.  The duty is equivalent to the consumptive irrigation requirement plus the return flow.  It is equivalent to the diversion plus channel losses in delivering water to the farm headgate.
 

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effluent 
Water or other liquid flowing from a reservoir, basin, or treatment plant. 
EPA 
The U.S. Environmental Protection Agency. 

 

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filtration 
The process of removing particulate matter from water by passing it through a porous medium. 
finished water 
Water that has been processed in a water treatment plant and is ready for delivery to consumers. 
fresh water 
Water that contains less than 1,000 mg/l total dissolved solids. 

 

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GAC 
See granular activated carbon adsorption 
geological log 
A detailed description of all underground features discovered during the drilling of a well, including types of formations encountered and their physical characteristics. 
geothermal water
Ground water that is hotter than the natural geothermal gradient at the location at which it occurs.
gpd 
Gallons per day, a measure of flow. 
granular activated carbon adsorption 
Treatment process wherein water is passed through granules of activated carbon. Contaminants such as VOCs adhere to the carbon and are removed from the water. 
grey water 
Wastewater other than sewage, such as sink, shower, or washing machine drainage. 
groundwater, ground water 
Water occurring beneath the earth's surface. 
groundwater basin 
Interconnected permeable geologic material capable of storing a significant ground-water supply surrounded by less permeable material.

ground-water mining 

The pumping of more ground water from an aquifer than in replaced by recharge

 

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hard water 
Alkaline water containing dissolved salts that interfere with some industrial processes and prevent soap from lathering. 
hardness
The levels of hardness in terms of parts per million of dissolved calcium carbonate are:
    0-75      ppm       Soft
            75-150     ppm      Moderately hard
150 - 300 ppm      Hard
           300 +        ppm      Very hard

Horton's Law of Stream Numbers
Within a drainage basin, the largest stream has a rank order of one.  Tributaries to rand order 1 streams have a rank order of 2 and so on.  The rank order of streams within a drainage basin has a log-normal probability density function.
hydraulic conductivity 
A measure of the rate at which water can move through a permeable medium if the hydraulic gradient of the ground-water flow system is unity (45 degrees)
hydraulic gradient 
The slope of the water table at a particular point. 
hydrologic cycle 
The natural process by which water cycles from the atmosphere to the earth (via precipitation), and back to the atmosphere again (via evaporation and other processes). 
hydrology 
The study of the occurrence, distribution, circulation, and characteristics of natural waters of the earth. 
hydrosphere
The liquid and solid water that rests on the lithosphere, including the solid, liquid, and gaseous materials that are suspended or dissolved in the water.

 

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impermeable 
Describes material or soil that does not allow, or allows only with great difficulty, the movement or passage of water. Compare permeable
imported water 
Water brought into an area from a distant source. 
in situ treatment 
Water treatment conducted in place, as opposed to removal of the water to another location for treatment. 
infiltration 
The flow of water downward from the land surface into and through the upper soil layers. 
influent 
Water or other liquid flowing into a reservoir, basin, or treatment plant. 
inorganic 
Describes material that is of mineral origin. Specifically, describes chemical compounds that do not contain carbon and hydrogen. Compare organic
instream uses 
Water uses that can be carried out without removing the water from its source, such as navigation and recreational uses. 
isohyetal line
A line on land or water surface all points along which the same amount of precipitation falls.

 

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landfill 
A facility in which solid waste from municipal or industrial sources is disposed. 

Leachate
          T
he liquid that results from dissolution of contaminants as it passes through waste materials.

License

          The highest form or recognition of a perfected and vested water right issued by an administrative agency.

lithosphere
That part of the earth which is composed predominantly of rocks (either coherent or incoherent and including the disintegrated rock materials known as soils and subsoils), together with everything inside of this rocky crust.  In the lithosphere other materials - chiefly water and gases such as are found in the air - are intermingled with the materials that constitute the rocks and the soils, but rock and soil predominate.

 

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maximum contaminant level 
The highest level of a contaminant permissible in water in a public water system. 
master stream
The largest stream within a drainage basin into which all other streams flow.  In Horton's Law of Stream Numbers, the master stream has a rank order of 1.
MCL 
See maximum contaminant level
MCM
Millions of cubic meters
mg/l 
See milligrams per liter
mgd 
Million gallons per day, a measure of flow. 
milligrams per liter 
A measure of concentration of a dissolved substance. A concentration of 1 mg/l means that one milligram of a substance is dissolved in each liter of water. For practical purposes, this unit of measurement is equivalent to parts per million, or ppm. 
modeling 
Use of mathematical equations to simulate and predict real events and processes. 
monitoring well 
A well used either to collect water samples for purposes of water quality testing, or to measure groundwater levels. 
MODFLOW
A computer code developed by the U.S. Geological Survey for solving the mathematical equations that describe ground-water flow systems.  The program exists in many versions beginning with Modflow-88.
MOU 
Memorandum of Understanding. 
municipal waste 
Waste originating from a community. May be composed of domestic (sewage) and industrial wastewater. 
municipal water district 
A public entity which supplies water to its member water purveyors. 

 

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National Priorities List 
A list of high-priority contaminated sites targeted for remedial action by EPA. 
Naturally Pure Water
H2O together with solid, liquid, and gaseous materials which it holds in solution or suspension as it exists in the earth in its natural conditions.
non-community water system 
A public water system that is not a community water system. 
non-point source 
A source of pollution that does not have a single point of origin. Pollution from a farmer's field or from urban street runoff falls in this category. Compare point source
non-potable 
Describes water that may contain objectionable pollution, contamination, minerals, or infective agents and is considered unsafe or unsuitable for drinking. Compare potable
NPDES 
National Pollutant Discharge Elimination System. Established under the Clean Water Act of 1972, it provides for regulation and monitoring of municipal and industrial waste discharges through a permit system. 
NPL 
See National Priorities List 

 

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operable unit 
Term for each of a number of separate activities undertaken as part of a Superfund site cleanup. 
operation and maintenance costs 
The costs of operating a system such as a treatment plant. "O & M" costs are ongoing expenses, such as for repair or for employee salaries. Compare capital costs
organic 
Describes material that originates from plant or animal sources. Specifically, describes chemical compounds containing carbon and hydrogen. Compare inorganic
OU 
See operable unit
overdraft 
The pumping of water from a groundwater basin in excess of the supply coming into the basin. Such pumping results in continuing depletion of the groundwater and a lowering of the water table.

overlying right 
The name of a ground-water right in a riparian rights state where the surface owner also owns the underlying water in fee simple.

 

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packed tower aeration 
A variation of the air stripping treatment process. Water flows down through packing material, while air flows upward to "strip" VOCs from the water. 
parts per million 
A measure of concentration of a dissolved substance. Compare milligrams per liter
pathogen 
A microorganism capable of causing disease. 
percolation 
The slow seepage of water into and through the ground. 
permeability 
Describes the ability of rock or soil to transmit water. 
permeable 
Describes material or soil that allows the movement or passage of water through it. Compare impermeable
plume 
The area occupied by a ground-water contaminant after it has begun to spread, through diffusion or other forces, away from its point of origin. 
point source 
A stationary source or fixed facility from which pollutants are discharged. Compare non-point source
pollutant 
Any substance introduced into the environment that adversely affects the usefulness of a resource. 
pore space 
The space between mineral grains in a porous medium. 
potable 
Describes water that is safe and satisfactory for drinking and cooking. Compare non-potable water
potentially responsible party 
Any individual or company--including owners, operators, transporters, or generators--potentially responsible for or contributing to a spill or other contamination at a Superfund site. 
potentiometric surface 
The level to which water will rise in a well that penetrates an aquifer. In an unconfined aquifer, it is equivalent to the water table. 
ppm 
See parts per million
precipitation 
Atmospheric moisture, such as rain or snow, that falls to earth. 
primary treatment 
Initial stage of treatment of wastewater, primarily consisting of removal of settleable solids. 
prior appropriation 
A doctrine of water law which allocates the right to use water on a first-come, first-served basis. The doctrine was developed out of the system of administrative disposition of land grant.  Disputes were settled in favor of the party with the oldest grant. 
PRP 
See Potentially Responsible Party
public participation plan 
A formal plan describing public involvement activities concerning a State-led or State-funded cleanup site. 
public water system 
A system for the provision to the public of piped water intended for human consumption. Such system must have at least 15 service connections, or regularly serve an average of at least 25 individuals daily for at least 60 days out of the year. 

pueblo water rights 

Old Spanish doctrine which recognized the needs of communities set up as military outposts to a continually expanding and unlimited supply of water.

 

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receiving waters 
Bodies of water that receive runoff or wastewater discharges, such as streams, rivers, and lakes. 
recharge 
Process by which precipitation or applied water seeps or percolates into the groundwater system. 
reclaimed water 
Wastewater that has been treated and brought to a level of water quality that makes it suitable for further beneficial use. 
remedial action plan 
A formal plan of action for cleanup of a contaminated site. 
reservoir 
A natural or man-made holding area used to store, regulate, or control water. 
return flow 
The amount of water that returns to the surface or ground water system that is available for re-use.
RI/FS 
Remedial Investigation/Feasibility Study. 
ROD 
Record of Decision. 
runoff 
That part of precipitation, snow melt, or irrigation water that drains or flows off the land into streams or other surface waters. 

 

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Safe Drinking Water Act 
An Act passed by United States Congress in 1976 that establishes a cooperative program among local, state, and federal agencies to insure safe drinking water for consumers. It authorizes EPA to set drinking water standards (including maximum contaminant levels), and provides special protection to sole source aquifers. 
safe yield 
The annual quantity of water that can be taken from a source of supply without depleting the source beyond its ability to be replenished. 
salinity 
The relative concentration of dissolved salts in water. 
saturated zone 
The area below the water table where all open spaces are filled with water. Compare unsaturated zone
secondary treatment 
Stage of wastewater treatment wherein bacteria are used to break down organic materials and significantly reduce biochemical oxygen demand. 
semi-confined aquifer 
An aquifer that is partially confined or overlain by a formation of low permeability through which water can pass slowly. Compare confined aquifer, unconfined aquifer
sole-source aquifer 
An aquifer that supplies 50 percent or more of the drinking water for an area. 
spreading basin, spreading grounds 
A man-made basin or series of basins designed to retain water for the purpose of recharging groundwater supplies. 
spring (artesian)
Spring whose water issues under artesian pressure generally through fractures that penetrate from the land surface through a confining bed of rock and into more permeable water-bearing rock where the water is under greater than atmospheric pressure and where the pressure in the water-bearing rock is able to lift the water to the land surface. Example: Paradise Springs, Idaho; Great Springs, Montana.
spring (constant)
A spring that has a variability in discharge of not more than 25 percent over the course of a year.  Constant springs are fed large volumes of water in net positive storage in relation to the discharge rate and are not commonly affected by annual variation in seasonal precipitation. Example: Paradise Springs, Idaho, Ayios Isidheros, Cyprus.
spring (contact)
Spring where water flows to the surface from permeable material over the outcrop of less permeable or impermeable material that retards or prevents the downward percolation of the ground water and thus deflect it to the surface.  These springs are commonly thermal springs and discharge at uniform rates without great seasonal fluctuation.  They commonly occur along faults or other structural features such as axial fractures along the crests of anticlines.
spring (depression)
Spring where a depression exists below local water table or phreatic surface.
spring (fracture or tubular)
Spring where water flows to the surface through relatively large openings in the rocks where the openings are joint, faults or other fractures or solution features.  They are typical in igneous, volcanic, metamorphic, and granitic terrane as well as chemical sediments such as limestone, anhydrite and gypsum.  Tubular springs are more typical in chemical sedimentary rock and from lava tubes in basalt flows. Example, Red Bolling Springs, Kentucky, Otter Springs, Florida; Dumanli Springs, Antalya, Turkey.
spring (geyser)
Special kind of intermittent spring in which discharge of water occurs though increase in reservoir pressure by the flashing of superheated water into steam in subterranean voids until the pressure is high enough to blow water out of the void. Examples: Old Faithful, Yellowstone National Park, Wyoming.
spring (gravity)
Spring where the water flows under atmospheric pressure onto the surface.  Such springs commonly emanates from the intersection of the phreatic water table with the land surface. Examples: Olancha, California
spring (mound)
Spring where water emergent at the land surface under artesian flow upward along a fault or fracture where algal material and chemical deposition of dissolved calcium sulfate or calcium carbonate at the spring orifice rises in elevation over time as the mound of precipitate and vegetal material grows.  Examples: San Ysidro Hot Springs, San Ysidro, New Mexico
spring (seepage)
A spring  where water percolates from numerous small openings in permeable materials and where the discharge rate is usually low.  Example: Olancha, California.
spring (thermal)
Thermal springs are divided into hot springs and warm springs.  A hot spring has a water temperature in excess of 98 degrees Fahrenheit (37 degrees Centigrade).   Thermal springs owe their heat content to the natural geothermal heat created by the hot core of the earth and the decay of radioactive minerals in the lithosphere and to underground magma chambers in volcanic regions.  The water is heated by deep circulation within the lithosphere prior to rising along deep faults and fractures to the land surface under artesian pressure.  The maximum depth of circulation of thermal waters can be calculated from the chemistry of the emerging water. Examples: Paradise Springs, Paradise, Idaho; Jemez Hot Springs, Jemez, New Mexico.
spring (variable)
A spring  that has discharge rate that of more than 25 percent during the year.   A variable spring is one in which the volume of water in net positive storage is small compared to the discharge rate and where the volume of water in net positive storage is strongly influenced to the previous period of precipitation.  Example: Lehman Springs, Nevada; Kephalovrysos tis Kythreas, Cyprus; Figeh Springs, Damascus, Syria.
 
static water level 
The elevation or level of water in a well when the pump is not operating. 
Superfund 
See CERCLA
subsurface water
Water that exists in the lithosphere whether in the unsaturated or vadose zone, or the saturated zone.
supplemental water 
Imported water brought into an area to supplement local water supplies. 
surface water 
All water naturally open to the atmosphere that rests on the lithosphere either solid or liquid, including liquid water in rivers, streams, lakes, reservoirs and snow or ice on the surface or in glaciers, ice bergs and permafrost. 
sustainable yield
The amount of water use that can be sustained indefinitely because of annual replacement by surface water runoff or aquifer recharge.

 

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TDS 
See total dissolved solids
tertiary treatment 
An advanced stage of wastewater treatment designed to remove nutrients or other constituents remaining after secondary treatment. 
total dissolved solids 
All of the dissolved solids in a sample of water, measured by evaporating the sample and weighing the residue. 
transmissivity 
The rate at which water is transmitted through the total thickness of an aquifer under a unity hydraulic gradient. 

 

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unconfined aquifer 
An aquifer that does not have confining formations or layers. Compare confined aquifer, semi-confined aquifer
unsaturated zone 
The area between the land surface and water table in which pore spaces are not completely filled with water. Also known as the vadose zone. Compare saturated zone
UST 
Underground storage tank. 

 

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vadose zone 
See unsaturated zone
 
Virtual Water
Water that is consumed in food.
 
VOC 
See volatile organic compound
volatile organic compound 
One of several organic chemical compounds characterized by its ability to evaporate readily at normal temperatures. Includes various industrial solvents and degreasers such as TCE, PCE, and carbon tetrachloride. 

 

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wastewater 
The used water and solids that are the result of domestic or industrial uses of water. Includes municipal waste or sewage. 
water purveyor 
An agency or person that supplies water. 
water supply system 
A facility designed for the distribution of potable water, typically including storage tanks and a network of pipes. 
water table 
The level of ground water. The upper surface of the saturated zone in an unconfined aquifer. 
watershed 
The land area that drains into a stream. An area that contributes runoff to a specific body of water. Same as drainage basin, hydrologic basin. 
well 
A bored, drilled, or driven shaft, or a dug hole, whose purpose is to reach underground water supplies. 

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