Glossary of Water Terms

The groundwater community uses many uncommon and/or industry specific words and terms. Read on to gain a better understanding of groundwater vocabulary.

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

Abandoned well
A well whose use has been permanently discontinued or which is in a state of disrepair such that it cannot be used for its intended purpose.

Abatement
Reducing the degree or intensity of, or eliminating, pollution.

Acid
A substance that has the ability to react with bases to form salt. The pH of an acidic solution is less than 7. pH 7 is neutral (e.g., pure water)- acids are pH 0 to less than 7. Similarly, bases are greater than 7 to 14. The usual definition of an acid is ?any substance that can donate a hydrogen ion?.

Acid Deposition ("acid rain")
Water that falls to or condenses on the Earth's surface as rain, drizzle, snow, sleet, hail, dew, frost, or fog with a pH of less than 5.6.

Acidic
The condition of water or soil which contains a sufficient amount of acid substances to lower the pH below 7.0.

Acre-foot (AF)
A common water industry unit of measurement. An acre-foot is 325,851 gallons, or the amount of water needed to cover one acre with water one foot deep. An acre-foot serves annual needs of two typical California families.

Acrylamide (CH2CHCONH2)
An organic monomer used as a starting material for polymers that are used as
coagulants or filter aids. Its concentration in finished drinking water is controlled by limiting the allowable dose
of polymer that can be added to water.1

The Act
The Metropolitan Water District Act. State legislation signed into law by the governor on May 10, 1927, effective July 29, 1927. Metropolitan incorporated Dec. 6, 1928.

Active Ingredient
The component which kills or otherwise controls, targets pests in any pesticide product. Pesticides are regulated primarily on the basis of active ingredients.

Adjudication
A court determination of water rights for a groundwater basin or a stream; adjudication sets priorities during shortages.

Aeration
The addition of air to water or to the pores in soil.

Age Tank
A tank used to store a known concentration of a chemical solution for feed to a chemical feeder. Also known as a day tank.

Agricultural Pollution
The liquid and solid wastes from farming, including: runoff and leaching of pesticides and fertilizers; erosion and dust from plowing; animal manure and carcasses; crop residue; and debris.

Algae
Microscopic plants which contain chlorophyll and float or suspend in water. Excess algae growths can impact tastes and odors to potable water. Their biological activities affect the pH and dissolved oxygen of the water.

Alkali
Any of certain soluble salts, principally of sodium, potassium, magnesium, and calcium, that have the property of combining with acids from neutral salts and may be used in chemical water treatment processes.

Alkaline
The quality of being bitter due to alkaline content (pH is greater than 7).

Alum (Al2(SO4)3?14 H2O)
The common name for aluminum sulfate, a chemical used in the coagulation process to remove particles from water.1

Aluminum (Al)
A metallic element. Aluminum is the most abundant metal in the earth?s crust; it does not occur free in nature.

Aqueduct
Man-made canal or pipeline used to transport water.

Aquifer
An underground geologic formation of rock, soil or sediment that is naturally saturated with water; an aquifer stores groundwater.

Arsenic
A naturally occurring element in the environment. Arsenic in drinking water commonly comes from natural sources in the ground, but some can come from industrial pollution. At high concentrations it can cause cancer.

Assay
A test for a particular chemical or effect.

B

Bacterium
A microscopic unicellular organism that lacks a nuclear membrane. Some can cause disease.

Bacteria
Plural of bacterium.

Bailer
A 10- to 20-foot-long pipe equipped with a valve at the lower end. It is used to remove slurry from the bottom or the side of a well as it is being drilled.

Base
A substance that has a pH value between 7 and 14.

Bedrock
The solid rock that underlies all soil, sand, clay, gravel and other loose materials on the earth's surface. Unfractured bedrock is impermeable while fractured bedrock may store and transmit groundwater.

Blackwater
Water that contains animal, human or food wastes.

BMPs
Best management practices. Generally, a set of standardized efficiencies. At Met, refers to a set of water conservation measures agreed to by participants in the California Urban Water Conservation Council.

Bond
A promise to repay money borrowed, plus interest, over a specified period of time.

Bond Issue
A means of raising large amounts of money for major projects by selling bonds.

Brackish
A mixture of freshwater and saltwater.

Buffer
A solution or liquid whose chemical makeup neutralizes acids or bases without a great change in pH.

C

California Environmental Quality Act (CEQA)
Requires an assessment of the possible environmental impacts of projects.

California Plan
Officially "California?s draft Colorado River Water Use Plan," also sometimes called the "4.4 Plan." A planning document designed to reduce California?s reliance on surplus Colorado River water over the next 15 years through conservation, water transfers, and conjunctive use measures.

Call
To order, request or retrieve stored water; to call upon.

Capillarity
The process by which water rises through rock, sediment or soil caused by the cohesion between water molecules and an adhesion between water and other materials that "pulls" the water upward.

CBO
Community-based organization. Local organization with which Metropolitan works on mutually beneficial programs.

CUWCC
California Urban Water Conservation Council. Created to increase efficient water use statewide through partnerships among urban water agencies, public interest organizations and private entitites. The Council's goal is to integrate urban water conservation Best Management Practices into the planning and management of California's water resources.

Centrifuge
A mechanical device that uses centrifugal or rotational forces separate substances of different densities, such as solids from liquids or liquids from other liquids.

Cesspool
A covered hole or pit for receiving sewage.

CFS
Cubic Feet Per Second.

Chloramination
the treatment of a substance, such as drinking water, with chlorine and ammonia (chloramines) in order to kill disease-causing organisms.

Chloride (Cl?)
One of the major anions commonly found in water and wastewater. Its presence is often determined by ion chromatographic or volumetric analysis. Consumers who drink water with concentrations of chloride exceeding a secondary maximum contaminant level of 250 milligrams per liter may notice a salty taste.

Chlorination
The treatment of a substance, such as drinking water, with chlorine in order to kill disease-causing organisms.

Chromium
A naturally occurring element found in air, soil, water and food.

Chromium VI
Aka "chrome 6." One of the most common species of chromium, chromium VI is known to cause cancer through exposure to airborne chromium compounds in industrial settings. The evidence of its carcinogenicity by ingestion is not compelling. The U.S. Environmental Protection Agency determined that chromium VI was not carcinogenic by ingestion.

Clarity
Clearness of liquid, as measured by a variety of methods.

CII
Metropolitan?s water conservation program for commercial, industrial and institutional entities.

Coachella
Coachella Valley Water District. Primarily agricultural irrigation district receiving Colorado River water through Coachella Canal and serving portions of Riverside, Imperial and San Diego counties north of the Salton Sea. Has priority 3(b) to California?s apportionment of Colorado River water, after (1) PVID; (2.) U.S. Bureau of Reclamation?s Yuma Project; (3a) Imperial Irrigation District. MWD has fourth priority.

Coagulation
The process, such as in treatment of drinking water, by which dirt and other suspended particles become chemically ?stuck together? so they can be removed from water.

Coliform bacteria
Bacteria of the family Enterobacteriaceae, commonly found in the intestinal tracts of warm-blooded animals. In sanitary bacteriology, these organisms are defined as all aerobic and facultative anaerobic, gram-negative, nonspore-forming, rod-shaped bacteria that ferment lactose with gas and acid formation within 48 hours at 95° Fahrenheit (35° Celsius).

Color
A physical characteristic describing the appearance of water (different from turbidity, which is the cloudiness of water). Color is frequently caused by fulvic and humic acids.

Combined Sewers
A sewer system that carries both sewage and storm-water runoff.

Condensation
Water vapor changing back into liquid.

Condensation Surfaces
Small particles of matter, such as dust and salt suspended in the atmosphere, which aid the condensation of water vapor in forming clouds.

Confined Aquifer
An aquifer that is bound above and below by dense layers of rock and contains water under pressure.

Conjunctive Use
Storing imported water in a local aquifer, in conjunction with groundwater, for later retrieval and use.

Contour Plowing
Plowing done in accordance with the natural outline or shape of the land by keeping the furrows or ditches at the same elevation as much as possible to reduce runoff and erosion. Control (1) A condition in which specific quality criteria have been achieved in a laboratory analysis. (2) A type of sample used to assess the quality of an analytical process.

Corrosivity
An indication of the corrosiveness of water. The corrosiveness of water is described by the water?s pH, alkalinity, hardness, temperature, total dissolved solids, dissolved oxygen concentration, and Langelier saturation index.

Cost Effective
Able to at least pay for itself or make a profit.

County Water Authority
A public water district serving a county-wide area.

CRA
Colorado River Aqueduct, built 1933-1941 and owned and operated by the Metropolitan Water District of Southern California.

Cryptosporidium
A group of widespread intestinal coccidian protozoan parasites about 5 micrometers in diameter, causing diarrhea and capable of infecting humans, birds, fish, and snakes. It is responsible for waterborne disease outbreaks.

CRWUA
Colorado River Water Users Association. CRWUA is a non-profit, non-partisan organization, formed to plan, study, formulate and advise on ways to protect and safeguard the interests of all whom use the Colorado River.

CT
The product of disinfectant concentration (in milligrams per liter) determined before or at the first customer and the corresponding disinfectant contact time (in minutes). It is also called the CT value. Units are milligram minutes per liter.

Cubic foot
A frequent water industry term of measurement, as in cubic feet per second. One cubic foot (cf) equals 7.48 gallons. A cubic foot per second is 450 gallons per minute.

CUWA
California Urban Water Agencies. Group of 11 member agencies serving two-thirds of state's population.

CVP
Central Valley Project. A series of dams, reservoirs and canals in the San Joaquin Valley of California.

Cyst
The infectious stage for Giardia, 7 to 10 micrometers long and refractile to light when viewed with a brightfield microscope.

D

Delta
Fan-shaped area at the mouth of a river.

Deposition
The process of dropping or getting rid of sediments by an erosional agent such as a river or glacier; also called sedimentation.

Desalination
The process of removing salt from seawater or brackish water.

Diemer
Robert B. Diemer, Metropolitan general manager 1952-1961, after whom Metropolitan treatment plant at Yorba Linda, in Orange County, was named.

Discharge
the amount of water flowing past a location in a stream/river in a certain amount of time - usually expressed in liters per second or gallons per minute.

Disinfectant
An agent that destroys or inactivates harmful microorganisms.

Disinfection By-Product (DBP)
A chemical by-product of the disinfection process. Disinfection by-products are formed by the reaction of the disinfectant, natural organic matter, and the bromide ion (Br?). Some disinfection by-products are formed through halogen (e.g., chlorine or bromine) substitution reactions; i.e., halogen-substituted by-products are produced. Other disinfection by-products are oxidation by-products of natural organic matter (e.g., aldehydes
RCHO). Concentrations are typically in the microgram-per-litre or nanogramper-litre range.

Disinfection By-Product Precursor (DBPP)
A substance that can be converted into a disinfection by-product during disinfection. Typically, most of these precursors are constituents of natural organic matter. In addition, the bromide ion (Br?) is a precursor material. See also bromide; disinfection by-product; natural organic matter.

Domenigoni
The name of a pioneer family in southwestern Riverside County and of one of the two valleys dammed to create Diamond Valley Lake, Metropolitan?s major reservoir near Hemet in southwestern Riverside County.

DRIP
Desalination Research and Innovation Partnership. A landmark research partnership among the water and electric industries, state and federal agencies and academia.

Drought
A prolonged period of below-average precipitation.

DVL
Diamond Valley Lake. Metropolitan?s major reservoir near Hemet, in southwestern Riverside County.

DWR
California Department of Water Resources. Guides development and management of California?s water resources; owns and operates State Water Project and other water-development facilities.

E

Ecosystem
An interacting network of groups of organisms together with their nonliving or physical environment.

Effluent
Water flowing from a structure such as a treatment plant. Contrast with influent.1Effluent
Water flowing from a structure such as a treatment plant. Contrast with influent.1

EIR
Environmental Impact Report; a state-mandated written summary of the positive and negative effects on the environment caused by the construction and operation of a project.

Endangered Species
A species of animal or plant threatened with extinction.

Epichlorohydrin (chloropropylene oxide, C3H5OCl)
A highly volatile, unstable liquid epoxide. It is a major raw material for epoxy and phenoxy resins and has other industrial uses. It is a treatment chemical that is regulated in drinking water under the Phase II Rule for synthetic organic contaminants and inorganic contaminants.

Erosion
The processes of picking up, moving, shaping and depositing sediments by various agents; erosional agents include streams, glaciers, wind and gravity.

Escherichia coli (E. coli)
A gram-negative, facultatively anaerobic, nonspore-forming bacillus commonly found in the intestinal tracts of humans and other warm-blooded animals. In sanitary bacteriology, Escherichia coli is considered the primary indicator of recent fecal pollution.

Evaporation
Water changing into vapor and rising into the air.

F

Fallowing
A program to generate water by paying farmers to fallow land, i.e., not grow crops. The water not used for irrigation is then transferred to urban areas or stored for future use.

Fecal Coliform (FC)
Members of the total coliform group of bacteria that are characterized by their ability to ferment lactose at 112.1° Fahrenheit (44.5° Celsius) and that are considered more specific indicators of fecal contamination than are coliforms that ferment lactose only at 95° Fahrenheit (35° Celsius). Escherichia coli and some Klebsiella pneumoniae strains are the principal fecal coliforms.

FERC
Federal Energy Regulatory Commission. An independent regulatory agency within the Department of Energy.

Ferric Chloride(FeCl3)
An iron salt used as a coagulant in water treatment. The iron has a valence of +3.1

Filtration
passing water through coal, sand and gravel to remove particles.

Fish Ladder
A device to help fish swim around a dam.

Fishery
The aquatic region in which a certain species of fish lives.

Floc
Clumps of impurities removed from water during the purification process; formed when alum is added to impure water.

Flocculation
A step in water filtration in which alum is added to cause particles to clump together.

Floodplain
Area formed by fine sediments spreading out in the drainage basin on either side of the channel of a river as a result of the river?s fluctuating water volume and velocity.

Fluoride Ion (F-)
A halide ion. Fluoride salts are added to drinking water for fluoridation. Fluoride is regulated by the US Environmental Protection Agency.

G

Gene
Aka Gene Camp. Small community on the California bank of the Colorado River, near Parker Dam and Lake Havasu, at and around which are located facilities of Metropolitan?s Colorado River Aqueduct. Reputedly the first name of a miner who had established "Gene?s Camp" at the site.

Giardia
The genus name for a group of single-celled, flagellated, pathogenic protozoas found in a variety of vertebrates, including mammals, birds, and reptiles. These organisms exist either as trophozoites or as cysts, depending on the stage of the life cycle.

Glacial Striations
Lines carved into rock by overriding ice, showing the direction of glacial movement.

Gross Alpha (a) Particle Activity
The total radioactivity caused by alpha particle emission as inferred from measurements on a dry sample. It is regulated by the US Environmental Protection Agency.

Gross Beta (b) Particle Activity
The total radioactivity caused by beta particle emission as inferred from measurements on a dry sample. It is regulated by the US Environmental Protection Agency.

Groundwater
Water that has percolated into natural, underground aquifers; water in the ground, not water puddled on the ground.

Groundwater Recharge or Replenishment
Pumping or percolating storm water runoff or imported water into an aquifer to replenish its supplies.

H

Haloacetic Acid (HAA)
(CX3COOH, where X = Cl, Br, H in various combinations) A class of disinfection by-products formed primarily during the chlorination of water containing natural organic matter. When bromide (Br?) is present, a total of nine chlorine-, bromine-and-chlorine-, or bromine-substituted species may be formed. Trihalomethanes and haloacetic acids are the two most prevalent classes of by-products formed during chlorination; and subject to regulation under the Disinfectant/Disinfection by-products rule.

Hardness
A characteristic of water determined by the levels of calcium and magnesium.

Heterotrophic Plate Count (HPC)
A bacterial enumeration procedure used to estimate bacterial density in an environmental sample, generally water. Other names for the procedure [within the water industry] include total plate count, standard plate count, plate count, and aerobic plate count.

Hinds
Julian B. Hinds, Metropolitan general manager 1941-1951, after whom the western-most of the five pumping plants along the Colorado River Aqueduct was named.

Hydroelectric Plant
a power plant that produces electricity from the power of rushing water turning turbine-generators.

Hydrology
the scientific study of the behavior of water in the atmosphere, on the Earth's surface and underground.

I

ICP
Innovative Conservation Program. The Innovative Conservation Program portion is designed to provide grants to explore the water savings potential and practicality of new water conserving technologies. Special consideration will be given to projects promoting water-landscape saving products or technologies.

IICP
Incremental Interruption and Conservation Plan, which was in effect during the state?s 1987-92 drought and was replaced by the WSDM Plan.

IID
Imperial Irrigation District, primarily agricultural irrigation district in Imperial County south of the Salton Sea. Has priority 3(a) to California?s apportionment of Colorado River water. Coachella has priority 3(b). MWD has fourth.

Immunofluorescence
The emission of visible light by a compound that has been irradiated with ultraviolet light. For example, a fluorescent compound (i.e., a fluorescein) can be attached to an antibody. Bacterial, viral, or other antigens that react with the antibody can then be observed by illuminating the sample with ultraviolet light.

I/O
Inlet-outlet facility at a reservoir.

Inorganic
Pertaining to material such as sand, salt, iron, calcium salts, and other mineral materials. Inorganic substances are of mineral origin, whereas organic substances are usually of animal or plant origin and contain carbon.

IRP
Integrated Resources Plan. The district?s plan to ensure reliable water delivery to its customer member agencies despite population growth, dry spells and droughts. The IRP resources mix includes water storage, conservation, best management practices (BMPs), recycling, desalination, and groundwater recovery, among others.

Irrigation
Supplying water to agriculture by artificial means, such as pumping water onto crops in an area where rainfall is insufficient.

ISP
Innovated Supply Program. The ISP will provide up to a total of $250,000 in grants on a competitive basis to stimulate and advance new innovative ideas that have potential to produce new sources of water supply for Southern Californa.

J

Jensen
Joseph Jensen, Metropolitan board chairman 1949-1974, after whom the Metropolitan treatment plant at Granada Hills, in Los Angeles County, was named.

L

Laguna Declaration
A Dec. 16, 1952 policy statement by Metropolitan?s Board of Directors that it will "provide its service area with adequate supplies of water to meet expanding and increasing needs in the years ahead."

Law of the River
A complex body of laws, court decrees, contracts, agreements, regulations and an international treaty used to govern allocation and management of Colorado River water.

Leach
To remove components from the soil by the action of water trickling through.

Legionella
A genus of bacteria of the family Legionellaceae. It currently consists of at least 51 serogroups comprising 34 species.1 It has the ability to colonize water in distribution systems (heating tanks, cooling towers, air conditioning lines, etc). It can cause disease in humans (e.g., Legionnaires? disease or Legionellosis) that is progressive and sometimes fatal, or a milder form of pneumonic illness (Pontiac fever) that is self-limited (i.e., heals on its own) with respiratory symptoms similar to influenza.

M

MAF
Million acre-feet.

Marginal Land
Land which, in its natural state, is not well suited for a particular purpose, such as raising crops.

MCL
Maximum Contaminant Level. According to health agencies, the maximum amount of a substance that can be present in water that's safe to drink and which looks, tastes and smells good.

Member Agency
One of 26 member public water providers associated with the Metropolitan Water District of Southern California, from which it purchases water and on whose board it is represented.

MGD
Million gallons per day, a measure used for water treatment plants and other facilities.

Microbiological
Relating to microorganisms and their life processes.1

Microorganism
An organism of microscopic size, such as bacterium.

Mills
Henry J. Mills, Metropolitan general manager 1967-1971, after whom Metropolitan treatment plant at Riverside was named.

Mitigation
A way in which an agency may offset negative environmental impacts of a project or make the impacts less serious.

Moab
A site near Moab, Utah, where a 10.5 million ton mountain of uranium mill tailings (scrap) is leaching pollutants, including uranium, into the nearby Colorado River.

Monterey Agreement
A December 1994 statement of principles to settle disputes over water allocations and operational aspects of the State Water Project, providing greater water management flexibility and financial stability.

MTBE
Methyl tertiary butyl ether. An oxygenate used in California gasoline to help prevent air pollution. The chemical has a long life and has been determined to have polluted lakes, reservoirs and groundwater after leaking from watercraft, underground tanks and pipelines. Required to be phased out by Dec. 31, 2002.

Mulch
Material spread on the ground to reduce soil erosion and evaporation of water; include hay, plastic sheeting and wood chips.

Municipal Water District
A public water provider governed by a locally elected board of directors, which supplies water to the public directly or through subagencies.

MWQI
Municipal Water Quality Investigation. Government agencies conduct water quality studies in the Sacramento watershed, the Sacramento-San Joaquin Delta, and the San Francisco Bay Area.

N

Natural Environment
All living and nonliving things that occur naturally on the earth.

Nitrate (NO3?)
An oxidized ion of nitrogen. Nitrifying bacteria can convert nitrite (NO2?) to nitrate in the nitrogen cycle. Sodium nitrate (NaNO3) and potassium nitrate (KNO3) are used as fertilizer. The nitrate ion is regulated by the US Environmental Protection Agency.

Nitrite (NO2-)
An intermediate oxidized ion of nitrogen. Nitrifying bacteria can convert ammonia (NH3) to nitrite (NO2?) to nitrate (NO3?) in the nitrogen cycle. Sodium nitrite (NaNO2) is used in curing meats. The nitrite ion is regulated by the US Environmental Protection Agency.

Nonpoint Source Pollution
Pollution which comes from diffuse sources such as urban and agricultural runoff.

NWRA
National Water Resources Association. Advocates federal policies, legislation and regulations promoting the development, management, protection and beneficial use of water resources.