Glossary A-F

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absorb—to take in.

acid—A substance having a pH less than l.0. Liquids are sour and corrosive.

acid rain—Rain with a pH of less than 5.6; results from atmospheric moisture mixing with sulphur and nitrogen oxides emitted from burning fossil fuels or from volcanic activity.

activated sludge—sludge particles produced by the growth of microorganisms in aerated tanks as a part of the process to treat wastewater.

acre-foot—a volume of water equal to the amount that would cover 1 acre to a depth of 1 foot or 325,851 gallons. An acre-foot of water is enough for a family of five for 1 year.

aeration—the addition of air to water. It lets gases trapped in the water escape and adds oxygen to the water, as in the first step of drinking water treatment.

aerobic—with oxygen; needing oxygen for cellular respiration.

Alfred Merritt Smith Water Treatment Facility (AMSWTF)—The Southern Nevada Water System's water treatment facility located near Saddle Island on the shore of Lake Mead. First put into operation in 1971, the AMSWTF treats and transmits Colorado River water to the Las Vegas Valley.

algal bloom—a sudden increase in the amount of algae, usually causing large floating masses to form. Algal bloom can affect water quality by lowering dissolving oxygen (DO) content and decreasing sunlight penetration. The blooms are usually caused by excessive nutrient addition and can be characteristic of a eutrophic lake.

alkaline—Having a pH greater than 7.0. Liquids are caustic and bitter.

alluvial—an adjective referring to the process of depositing soil or earth material by running water, as in a riverbed, flood plain or delta.

alum—aluminum salt used as flocculating agent.

anaerobic—in the absence of oxygen; able to live and grow where there is no air or free oxygen, as certain bacteria.

aquatic—living or growing in or on water.

aqueduct—a pipe or conduit made for conveying water.

aquifer—a layer of underground sand, gravel or porous rock through which water flows slowly. Use of the term is usually restricted to those water-bearing structures capable of yielding water in sufficient quantity to constitute a usable supply.

aquifer confined—an aquifer which is bounded above and below by formations of impermeable or relatively impermeable material.

aquifer recharge—the addition of water by any means to an aquifer.

artesian aquifer—an aquifer that is sandwiched between two layers of impermeable materials and is under great pressure, forcing the water to rise without pumping. Springs often surface from artesian aquifers.

artesian well—a well that taps a confined aquifer where the water in the aquifer is under sufficient pressure to force the water to the surface.

artesian zone—a zone where water is confined in an aquifer under pressure so the water will rise in a well casing or drilled hole above the bottom of the confining layer overlying the aquifer.

artificial groundwater recharge—The process of injecting treated water through a well into the groundwater. Artificially recharged groundwater is measured and recorded as banked groundwater recharge, which can be recovered at a later time.

A B C D E F

banked groundwater recharge—water that has been stored temporarily in the groundwater aquifer through a program of artificial groundwater recharge.

bicarbonate—an acid salt of carbonic acid.

bioaccumlation—the process by which a substance is taken up by an aquatic organism both from water and through food.

biochemical oxygen demand (BOD)—used to describe the amount of oxygen that will be consumed by microorganisms during the biological reaction of oxygen with organic materials.

biodegradable—capable of being decomposed (broken down) by natural biological processes.

biomagnification—bio-accumlation occurring through several levels of a food chain; process by which certain substances (such as pesticides or heavy metals) are deposited into a waterway, are eaten by aquatic organisms, which are in turn eaten by large birds, animals or humans, causing the substances to become increasingly concentrated in tissues or organs as they move up the food chain.

bioremediation—a biologically mediated corrective process that occurs naturally over time; humans may speed up this process through technology.

biosolids—sludge that is intended for beneficial use. Biosolids must meet certain government-specified standards depending on use as a fertilizer or as a soil additive.

brackish water—a mixture of salt and fresh water, usually found where rivers enter the ocean.

buoyancy—the ability of water to support weight and the degree to which it can support weight.

calcium carbonate—one of the most stable, common and widely-dispersed materials on Earth; occurs naturally in oyster & clam shells, calcite, limestone, marble, chalk, and other forms; used to express hardness and alkalinity of water.

capillary action—action by which the surface of a liquid in contact with a solid is elevated or depressed depending upon the attraction of the liquid's molecules for each other and for those of the solid (example: water in a capillary tube).

carbon dioxide—colorless, odorless gas made of carbon and oxygen; exhaled by animals and humans, utilized by plants in photosynthesis.

carbonic acid—substance formed by combining water and the carbon dioxide.

career—a chosen pursuit of life's work; a job or profession one is trained to do.

change of state—change of matter from one state (gas, liquid, solid) to another.

channel—a natural or artificial course for running water.

chemical—a substance, like chlorine, used to kill bacteria in the water.

chlorination—the addition of chlorine to water to destroy microorganisms.

chlorine—a chemical used to clean water.

chronic effects—adverse health effects that are the result of long-term exposure or those that are permanent or long-lasting.

clarifier—a vessel in which solids settle out of water by gravity during drinking water treatment processes.

coagulation—a process by which dirt and other small solid particles are stuck together with chemicals (forming "flocs") so that they can be removed from the water.

condensation—the changing of a gas or vapor into a liquid.

conserve—save, protect, keep; to use a resource wisely and efficiently.

conservation—act of using a resource only when needed for the purpose of protecting from waste of loss of the resource.

Clark County Department of Comprehensive Planning—The department of the Clark County government responsible for coordinating certain planning activities for the county, including responsibility for the regional wastewater management plan.

Colorado River Commission (CRC)—The Colorado River Commission represents the State of Nevada at all federal, interstate and international discussions regarding the management and operations of the Colorado River.

dehydrate—to take away water.

density—the ratio of an object's mass to its volume.

desalinization—the process of salt removal from sea or brackish water.

desert—an area of land with very little precipitation (rain or snow).

dilution—the process of adding a known amount of a solvent (usually water) to another solution to make it less concentrated.

disinfection—the final step at a water treatment plant; disinfection kills any organism that may be harmful.

dissolved oxygen (DO)—oxygen gas dissolved in water.

distillation—the separation of different substances in a solution by boiling off those of low boiling points first. For example, water can be distilled and the steam condensed back into a liquid that is almost pure water. The impurities (minerals) remain in the concentrated residue.

distilled water—water that has undergone the process of evaporation and condensation and has had the minerals removed.

drainage basin—land area where precipitation runs off into streams, rivers, lakes and reservoirs. It is a land feature that can be identified by tracing a line along the highest elevations between two areas on a map, often a ridge. Also called a "watershed."

drip irrigation—above ground, low-pressure watering system with flexible tubing that releases small, steady amounts of water through emitters placed near individual plants.

drought—a prolonged period of dry weather; a lack of rain; nature's failure to fulfill the water wants and needs of man.

A B C D E F

ecosystem——the relationship between all the parts (living and nonliving) within an environmental community.

effluent—water that flows from a lagoon, tank, or wastewater treatment process.

environment—surroundings.

Environmental Impact Statement (EIS)—a detailed written statement, required by Section 102(2)(c) of the National Environmental Policy Act. Analyzes the environmental impacts of a proposed action, adverse effects that cannot be avoided, alternative courses of action, short-term uses of the environment versus the maintenance of enhancement of long-term productivity, and any irreversible and irretrievable commitment of resources.

erosion—the wearing away of land surface by wind, water, ice or other geologic agents. This occurs naturally from weather or runoff but is often intensified by human land use practices.

estuary—an area where fresh water meets salt water, such as with bays, mouths of rivers, salt marshes and lagoons.

eutrophic—refers to a body of water characterized by nutrient-rich water supporting abundant growth of algae and/or other aquatic plants.

eutrophication—see eutrophic; the natural aging cycle of lakes, normally taking centuries to accomplish, but can be accelerated when outside sources of nutrients are added such as wastewater, fertilizer or feed lot runoff.

evaporate—to convert or change into a vapor.

evaporation—the change of matter from liquid to the gaseous or vaporous state; the process by which water becomes a vapor at a temperature below the boiling point.

faucet—a device (that can be controlled to stop the flow of water) through which water flows into a sink or other basin.

fecal coliform bacteria—a type of coliform bacteria found in the intestines of humans and other warm-blooded animals that aids in the digestion process. It is used as an indicator of fecal contamination and the possible presence of pathogens.

feed lots—confined areas where many livestock may be kept.

filtration—a process that removes most of the solid impurities remaining in water after coagulation and sedimentation have taken place.

filter—something that helps separate out unwanted things from water.

flow—move smoothly.

forebay—a storage tank or small reservoir constructed specifically to establish a stable operating supply of water for the intake of a pumping station.

fresh water—inland water that has a low concentration of minerals, salts and dissolved solids (below 0.01 percent).

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