Water Definitions

absolute water right
A property right to put water to beneficial use with a specified priority date.

acre-foot
A volume of water equal to one foot in depth covering an area of one acre.  Also 43,560 cubic feet, or 325,851 gallons. Used to measure stored water quantities.

adjudication
To hear and settle a case by judicial procedure.

algae
Chlorophyll-bearing nonvascular, primarily aquatic species that have no true roots, stems, or leaves; most algae are microscopic, but some species can be as large as vascular plants.

alkali
A soluble salt or a mixture of soluble salts present in some soils of arid regions in quantity detrimental to agriculture.

alkalinity
Generally, refers to the sum of the concentration of bicarbonate and carbonate of an aqueous solution.

alluvial aquifer
A water-bearing deposit of unconsolidated material (sand and gravel) left behind by a river or other flowing water.

alluvium
Deposits of clay, slit, sand, gravel or other particulate rock material left by a river in a streambed, on a flood plain, delta, or at the base of a mountain.

amalgamation
The dissolving or blending of a metal (commonly gold and silver) in mercury to separate it from its parent material.

ambient
Natural concentration of water quality constituents prior to mixing of either point or nonpoint source load of contaminants or completely enveloping. From a time series of measurements of a parameter at a given location the ambient value is the 85th percentile.

ammonia
A compound of nitrogen and hydrogen (NH₃) that is a common by-product of animal waste. Ammonia readily converts to nitrate in soils and streams.

anomalies
As related to fish, externally visible skin or subcutaneous disorders, including deformities, eroded fins, lesions and tumors.

appropriate
(verb) To take the legal actions necessary to create a right to take water from a stream, tributary or aquifer for application to beneficial use.

appropriation
The right to take water from a stream, tributary or aquifer for beneficial use at a specified rate of flow, either for immediate use or to store for later use.  Usually evidenced by a water court decree.

aquatic guidelines
Specific levels of water quality which, if reached, may adversely affect aquatic life. These are non-enforceable guidelines issued by a governmental agency or other institution.

aquifer
An underground deposit of sand, gravel or rock through which water can pass or is stored.  Aquifers supply the water for wells and springs.

artificial recharge
Augmentation of natural replenishment of ground-water storage by some method of construction, spreading of water, or by pumping water directly into an aquifer.

atmospheric deposition
The transfer of substances from the air to the surface of the Earth, either in wet form (rain, fog, snow, dew, frost, hail) or in dry form (gases, aerosols, particles).

augmentation plan
A court-approved plan that allows a water user to divert water out of priority so long as adequate replacement is made to the affected stream system preventing injury to the water rights of senior users.

augmentation source
The supply of water used to replace out-of-priority depletions.

bank
The sloping ground that borders a stream and confines the water in the natural channel when the water level, or flow, is normal.

base flow
Sustained, low flow in a stream; grount-water discharge is the source of base flow in most places.

basic fixed sites
Sites on streams at which stream flow is measured and samples are collected for temperature, salinity, suspended sediment, major ions and metals, nutrients, and organic carbon to assess the broad-scale spatial and temporal character and transport of inorganic constituents of stream water in relation to hydrologic conditions and environmental settings.

basin
See drainage basin.

basin and range physiographic
A region characterized by a series of generally north-trending mountain ranges separated by alluvial valleys.

bed load
Sediment that moves on or near the streambed and is in almost continuous contact with the bed.

beneficial use
Application of water without waste for human or natural benefit.

Best management practice (BMP)
An agricultural practice that has been determined to be an effective practical means of preventing or reducing nonpoint source pollution.

Biomass
The amount of living matter, in the form of organisms, present in a particular habitat, usually expressed as weight per unit area.

Biota
Living organisms.

Call
The exercise of a senior water right holder of "calling" for his or her water rights, requiring upstream junior water right holders to allow water to flow to the senior right holder.

Canopy angle
Generally, a measure of the openness of a stream to sunlight. Specifically, the angle formed by an imaginary line from the highest structure (for example: tree, shrub, or bluff) on one bank to eye level at midchannel to the highest structure on the other bank.

Carbonate rocks
Rocks (such as limestone or dolostone) that are composed primarily of minerals (such as calcite and dolomite) containing the carbonate ion (CP₃²-).

Center pivot irrigation
An automated sprinkler system involving a rotating pipe or boom that supplies water to a circular area of an agricultural field through sprinkler heads or nozzles.

Channelization
Modification of a stream, typically by straightening the channel, to provide more uniform flow; often done for flood control or for improved agricultural drainage or irrigation.

Clean Water Act
The federal law that sets forth how the United States will restore and maintain the chemical, physical and biological integrity of the country's waters (oceans, lakes, streams and rivers, ground water and wetlands).  The law provides protection to the country's surface waters from both point and non-point sources of pollution.

Climate
The sum total of the meteorological elements that characterize the average and extreme conditions of the atmosphere over a long period of time at any one place or region of the Earth's surface.

Colorado Doctrine
see appropriation.

Colorado Water Conservation Board
The state agency vested with the authority to appropriate water of streams and lakes in amounts that are determined to be necessary to preserve the natural environment to a reasonable degree.

Combined sewer overflow
A discharge of untreated sewage and storm water to a stream when the capacity of a combined storm/sanitary sewer system is exceeded by storm runoff.

Compact
A contract between states that is ratified by those states' legislatures and by the U.S. Congress. The contract controls the division of water in a river system that flows across state boundaries.

Concentration
The amount or mass of a substance present in a given volume or mass of sample. Usually expressed as microgram per liter (water sample) or micrograms per kilogram (sediment or tissue sample).

conditional water right
The legal preservation of a priority date that provides a water user time to develop his or her water right, but reserves a more senior date.  A conditional right becomes an absolute right when water is actually put to beneficial use.

conservancy district
Established by decree of a court under the Water Conservancy District Act of 1937.  A conservancy district can obtain rights-of-way for works; contract with the United States or otherwise provide for construction of facilities; assume contractual or bonded indebtedness;  administer, operate, and maintain physical works; have authority to conserve, control, allocate, and distribute water supplies; and have contracting and limited taxing authority to derive the revenues necessary to accomplish its purposes. There are currently 45 conservancy districts in Colorado.

conservation district
Established under specific statues by the Colorado General Assembly. There are currently three conservation districts in Colorado;  the Colorado River Water Conservation District, the Southwestern Water Conservation District, and the Rio Grande Water Conservation District.  The mission is to oversee the conservation, use, and development of water in large geographical areas of the state.

consumptive use
Any use of water that permanently removes water from the natural stream system.

Continental Divide
An imaginary boundary line that runs north-south along the crest of the Rocky Mountains, separating river and drainages that flow west to the Pacific Ocean from those that flow south and east to the Gulf of Mexico.

cubic feet per second (cfs)
Rate of water discharge representing a volume of 1 cubic food passing a given point during 1 second, equivalent to approximately 7.48 gallons per second or 448.8 gallons per minute or 0.02832 cubic meter per second.

decree "water"
A court decision about a water right that is then administered by Colorado's Water Resources Department.

direct flow (also direct right)
Water diverted from a river or stream for use without interruption between diversion and use except for incidental purposes, such as settling or filtration.

discharge
Rate of fluid flow passing a given point at a given moment in time, expressed as volume per unit of time.

diversion
The removal of water from its natural course or location, or controlling water in its natural course or location by means of a ditch, canal, flume, reservoir, bypass, pipeline, conduit, well, pump or other device.

drainage basin
The portion of the surface of the Earth that contributes water to a stream through overland run-off, including tributaries and impoundments.

drawdown
The difference between the water level in a well before pumping and the water level in the well during pumping. Also, for flowing wells, the reduction of the pressure head as a result of the discharge of water.

drinking water standard or guideline
A threshold concentration in a public drinking-water supply, designed to protect human health. As defined here, standards are U.S. Environmental Protection Agency regulations that specify the maximum contamination levels for public water systems required to protect the public welfare; guidelines have no regulatory status and are issued in an advisory capacity.

drip irrigation
An irrigation system in which water is applied directly to the root zone of plants by means of applicators (orifices, emitters, porous tubing, perforated pipe, and so forth) operated under low pressure. The applicators can be placed on or below the surface of the ground or can be suspended from supports.

drought
A long period of below-average precipitation.

due diligence
The efforts necessary to complete a water appropriation action that demonstrates a good faith action to complete a diversion of water within a reasonable time period.

Ecological studies
Studies of biological communities and habitat characteristics to evaluate the effects of physical and chemical characteristics of water and hydrologic conditions on aquatic biota and to determine how biological and habitat characteristics differ among environmental settings.

Ecoregion
An area of similar climate, landform, soil, potential natural vegetation, hydrology, or other ecologically relevant variables.

effluent
Outflow from a particular source, such as a stream that flows from a lake or liquid waste that flows from a factory or sewage-treatment plant.

effluent exchange
The practice of using wastewater effluent from transbasin water, non-tributary water sources, or other sources without causing injury to other water rights as a replacement source of water for diversion of water farther upstream that would otherwise have been out of priority.

Endangered Species Act
The federal law that governs how animal and plant species whose populations are dangerously in decline or close to extinction will be protected and recovered.  The law protects not only threatened and endangered species, but also the ecosystems upon which they depend.

Energy Policy Act (EPACT)
A 1992 federal law that states, among other things, that no toilet for household use manufactured after Jan. 1, 1994, shall use more than 1.6 gallons per flush and that shower heads and faucets manufactured after Jan. 1, 1994, may not use more than 2.5 gallons per minute.

exchange
A process by which water, under certain conditions, may be diverted out of priority at one point by replacing it with a like amount of water at another point.

exempt wells
Those wells that are exempt from water rights administration under a priority system (examples of exempt wells are household use only, domestic and livestock wells, and pre 1972 unregistered wells ).

firm annual yield
The yearly amount of water that can be dependably supplied from the raw water sources of a given water supply system.

futile call
A situation in which a junior ( more recent) priority is allowed to continue to divert in spite of a downstream senior call because curtailing the junior would not reasonably produce any additional water for the senior.

ground water
Water found below the earth's surface.

hydrologic cycle
The movement of water from the atmosphere to the earth and back again to the atmosphere. The three stages are precipitation, runoff or infiltration and evaporation.

instream flows
Water flowing in its natural stream bed, such as water required for maintaining flowing streams, or for fish.

junior rights
Water rights that are more recent than older or more senior rights.

Mean discharge (MEAN)
The arithmetic mean of individual daily mean discharges during a specific period, usually daily, monthly, or annually.

Monitoring well
A well designed for measuring water levels and testing ground-water quality.

National Pollution Discharge Elimination System (NPDES) Permit
A permit required under Section 401 of the Clean Water Act regulating discharge of pollutants to the nation's waterways.

National Environmental Policy Act (NEPA)
The federal law enacted to ensure the integration of natural and social sciences and environmental design in planning and decision-making for projects that may impact the quality of the human environment.

non-consumptive use
Water drawn for use that is not consumed, for example, water withdrawn for purposes such as hydropower generation. It also includes uses such as boating or fishing where the water is still available for other uses at the same site.

non-exempt wells
Those that  are governed by the priority system and may be curtailed (included any other type of well not considered exempt).

non-point source
Pollution discharged over a wide land area, not from one specific location.  Runoff from city streets, parking lots, home lawns, agricultural land, individual septic systems and construction sites that finds its way into lakes and stream constitutes an important sources of water pollutants.

non-tributary ground water
Underground water that meets certain legislative criteria as to its effect on a stream system. 

point source
Pollutants discharged from any identifiable point, including pipes, ditches, channels, sewers, tunnels and containers of various types.

Outwash
Soil material washed down a hillside by rainwater and deposited upon more gently sloping land.

Perennial stream
A stream that normally has water in its channel at all times.

Point source
A source at a discrete location such as a discharge pipe, drainage ditch, tunnel, well, concentrated livestock operation, or floating craft.

potable
Water that is considered safe for domestic consumption; drinkable.

precipitation
Any or all forms of water particles that fall from the atmosphere, such as rain, snow, hail and sleet.

prior appropriation doctrine
A legal concept in which the first person to appropriate water and apply it to a beneficial use has the first right to use that amount of water from that source.  Each successive appropriator may only take a share of the water remaining after all senior water rights are satisfied.  This is the historical basis for Colorado water law and is sometimes known as the Colorado Doctrine or the principle of "first in time, first in right."

priority
The right of an earlier appropriator to divert from a natural stream in preference to a later appropriator.

priority date
The date of establishment of a water right.  The rights established by application have the application date as the date of priority.

raw water
Untreated water.

recharge
Water that infiltrates the ground and reaches the saturated zone.

reservoir
An impoundment of collected water controlled by a dam (raw water) or storage tank (potable water).

return flows
The unused portion of water that returns to a stream or river after a beneficial use.

reuse
To use again, to intercept for subsequent beneficial use--either directly or by exchange--water that would otherwise return to the stream system.

revegetate
To provide barren land with a new vegetative cover.

Riparian
Areas adjacent to rivers and streams with a high density, diversity, and productivity of plant and animal species relative to nearby uplands.

runoff
Water that flows on the earth's surface to streams, rivers, lakes, and oceans.

Safe Drinking Water Act (SDWA): Federal legislation that regulates the treatment of water for human consumption.  Requires testing for and elimination of contaminants to levels for the protection of human health.

Sediment
Particles, derived from rocks or biological materials, that have been transported by a fluid or other natural process, suspended or settled in water.

senior rights
Water rights that are staked the earliest with the water court.

sole source aquifer
A ground-water system that supplies at least 50 percent of the drinking water to a particular human population; the term is used to denote special protection requirements under the Safe Drinking Water Act and may be used by approval of the U.S. Environmental Protection Agency.

Specific conductance
A measure of the ability of a liquid to conduct an electrical current.

Stream flow
A type of channel flow, applied to that part of surface runoff in a stream whether or not it is affected by diversion or regulation.

subsurface drainage
A shallow drain installed in an irrigated filed to intercept the rising ground-water level and maintain the water table at an acceptable depth below the land surface.

surface water
Water present on the earth's surface.

system loss
An amount of water, expressed as a percentage, lost from a water storage or distribution system due to leaks, evaporation, seepage and unauthorized use.

transbasin diversion
The conveyance of water from its natural drainage basin into another basin for beneficial use.

transmountain diversion
The conveyance of water from one drainage basin to another across the Continental Divide.

treated water
Water that has been filtered and/or disinfected; sometimes used interchangeably with "potable" water.

tributary
A stream or river that flows into a larger one.

tributary drainage
The area from which water naturally drains by gravity into a water course.

tributary ground water
Water present below the earth's surface that is hydrologically connected to a natural surface stream.

urban runoff
Excess water that doesn't infiltrate the soil, but flows to a storm sewer or open waterway.

water and sanitation districts
A special taxing district formed by the residents of the district for the combined purpose of providing potable water and sanitary wastewater services.

water right: A property right to make beneficial use of a particular amount of water with a specified priority date.

watershed: An area from which water drains to a given stream or river or river system.

Wellhead Protection Program: An amendment to the federal Safe Drinking Water Act in 1986.  Initiated to minimize the potential for contamination of public ground water supplies.

wetlands: Areas with standing water of a high water table either permanently or for some significant period each year.  Generally includes swamps, marshes, bogs and areas with water-loving vegetation that grows in or around water.

Xeriscape: A landscape concept to describe beautiful landscaping that has low water needs. The term was developed by Denver Water in 1981. It is derived from the Greek word xeros, meaning dry.

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