Index: 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

activated carbon
the process of pollutants moving out of water and attaching on to activated carbon.

activated clay
a variety of argillaceous silicates with similar behavior under certain conditions, but modified in several ways to obtain the desired properties.

adhesion
the molecular attraction asserted between the surfaces of bodies in contact. Compare cohesion.

adsorption
the adhesion of a substance to the surface of a solid or liquid. Adsorption is often used to extract pollutants by causing them to be attached to such adsorbents as activated carbon or silica gel.

aeration
the mixing or turbulent exposure of water to air and oxygen to dissipate volatile contaminants and other pollutants into the air.

argillaceous
soils which are predominantly clay or abounding in clays or claylike materials.

air sparging
an in situ technology in which air is injected through a contaminated aquifer. Injected air creates an underground stripper that removes contaminants by volatilization, flushing (bubble) the contaminants up into the unsaturated zone where a vapor extraction system is usually implemented in conjunction with air sparging to remove the generated vapor phase contamination.

alkalinity
the measurement of constituents in a water supply which determine alkaline conditions. The alkalinity of water is a measure of its capacity to neutralize acids. See pH.

alumina
The native form of aluminum oxide occurring as corundum or in hydrated forms as a powder or crystalline substance.

aluminosilicates
members of any of the groups of the silicates of aluminum which have the same chemical makeup but with distinct characteristics in terms of refractory/flux and crystalline geometry owing to how each chain their elements’ atoms.

amines
a class of organic compounds of nitrogen that may be considered as derived from ammonia (NH3) by replacing one or more of the hydrogen atoms by organic radicals, such as CH3 or C6H5, as in methylamine and aniline. The former is a gas at ordinary temperature and pressure, but other amines are liquids or solids. All amines are basic in nature and usually combine readily with hydrochloric or other strong acids to form salts.

anthracite
a dense, shiny coal that has a high carbon content and little volatile matter and burns with a clean flame. Also called hard coal.

attapulgite
attapulgite is a magnesium aluminum silicate clay of very fine particle size. It is also known as palygorskite or Fullers Earth and is closely related to Sepiolite mineral.

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B

backsiphonage
reverse seepage of water in a distribution system.

backwashing
reversing the flow of water through a home treatment device filter or membrane to clean and remove deposits.

BAT / BCL
Best Conventional Pollutant Control Technology - effluent limitations guidelines represent the best existing economically achievable performance of water treatment in an industrial subcategory or category.

bentonite clay
unique material composed essentially of montmorillonite clay, also known as hyrdous silicate of alumina

bituminous
A coal which is high in carbonaceous matter having a volatility greater than that of anthracite and a calorific value greater than that of lignite. In the US, it is often referred to as "soft coal".

biomonitoring
a test used to evaluate the relative potency of a chemical by comparing its effect on a living organism with the effect of a standard population on the same type of organism.

bioremediation
a process that uses living organisms to remove pollutants.

bioslurping
designed to withdraw groundwater, free product, and soil gas in the same process stream using a single pump. Groundwater is separated from the free product and is treated and discharged.

biosolids
a nutrient-rich organic material resulting from the treatment of wastewater. Biosolids contain nitrogen and phosphorus along with other supplementary nutrients in smaller doses, such as potassium, sulfur, magnesium, calcium, copper and zinc. Soil that is lacking in these substances can be reclaimed with biosolids use. The application of biosolids to land improves soil properties and plant productivity, and reduces dependence on inorganic fertilizers.

blackwater
wastewater from toilet, latrine, and agua privy flushing and sinks used for food preparation or disposal of chemical or chemical-biological ingredients.

blast enhanced fracturing
fractures are developed by fracturing beneath the surface in low permeability and over-consolidated sediments to open new passageways that increase the effectiveness of many in situ processes and enhance extraction efficiencies.

boiling point
the temperature at which a liquid boils. It is the temperature at which the vapor pressure of a liquid equals the pressure on its surface. If the pressure of the liquid varies, the actual boiling point varies. For water it is 212 degrees Fahrenheit or 100 degrees Celsius.

BTEX
BTEX is an acronym for benzene, toluene, ethylbenzene, and xzylene. This group of volatile organic compounds (VOCs) is found in petroleum hydrocarbons, such as gasoline, and other common environmental contaminants.

brine
highly salty and heavily mineralized water containing heavy metal and organic contaminants.

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C

calcium carbonate
CACO3 - a white precipitate that forms in water lines, water heaters and boilers in hard water areas; also known as scale.

carbonates
the collective term for the natural inorganic chemical compounds related to carbon dioxide that exist in natural waterways.

carbonized
to unite with carbon; turn into carbon, as by burning; "carbonize coal"

carcinogen
A substance or agent capable of causing or producing cancer in mammals, including humans.

cations
an atom or molecule has more protons (positively charged particles) than electrons (negatively charged particles), it has an overall positive charge and is called a cation.

CERCLA
Comprehensive Environment Response, Compensation and Liability Act. Also known as SUPERFUND. The Act gave EPA the authority to clean up abandoned, leaky hazardous waste sites.

certificate of water right
an official document which serves as court evidence of a perfected water right.

chlorination
the adding of chlorine to water or sewage for the purpose of disinfection or other biological or chemical results.

cholera
a disease from an intestinal infection caused by contaminated water or food. The symptoms are watery diarrhea, vomiting, muscle cramps, and severe dehydration.

coagulation
in water treatment, the use of chemicals to make suspended solids gather or group together into small flocs.

cohesion
a molecular attraction by which the particles of a body are united throughout the mass whether like or unlike. Compare adhesion.

coliform bacteria
nonpathogenic microorganisms used in testing water to indicate the presence of pathogenic bacteria.

colloids
finely divided solids which will not settle but which may be removed by coagulation or biochemical action.

conservation
to protect from loss and waste. Conservation of water may mean to save or store water for later use.

contamination
the introduction into water of sewage or other foreign matter that will render the water unfit for its intended use.

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D

deionized water
water free of inorganic chemicals.

desalination
the process of salt removal from sea or brackish water.

detection limit
the lowest level that can be determined by a specific analytical procedure or test method.

diluting water
distilled water that has been stabilized, buffered, and aerated.

discharge
the volume of water that passes a given point within a given period of time. It is an all-inclusive outflow term, describing a variety of flows such as from a pipe to a stream, or from a stream to a lake or ocean.

discharge permit
a permit issued by a state or the federal government to discharge effluent into waters of the state or the United States. In many states both State and federal permits are required.

disinfection
the killing of the larger portion of the harmful and objectionable bacteria in the sewage. Usually accomplished by introduction of chlorine, but more and more facilities are using exposure to ultraviolet radiation, which renders the bacteria sterile.

dissolve
the process by which solid particles mix molecule by molecule with a liquid and appear to become part of the liquid.

dissolved solids
inorganic material contained in water or wastes. Excessive dissolved solids make water unsuitable for drinking or industrial uses.

distilled water
water that has been treated by boiling and condensation to remove solids, inorganics, and some organic chemicals.

drainage area
of a stream at a specified location is that area, measured in a horizontal plane, enclosed by a topographic divide from which direct surface runoff from precipitation normally drains by gravity into the stream above the specified location.

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E

effective porosity
the portion of pore space in saturated permeable material where the movement of water takes place.

effluent
any substance, particularly a liquid, that enters the environment from a point source. Generally refers to wastewater from a sewage treatment or industrial plant.

environment
aggregate of external conditions that influence the life of an individual organism or population.

EPA
Environmental Protection Agency

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

estuary
thin zone along a coastline where freshwater system(s) and river(s) meet and mix with a salty ocean (such as a bay, mouth of a river, salt marsh, lagoon).

evaporation
the change by which any substance is converted from a liquid state and carried of in vapor. Compare condensation, sublimation.

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F

fecal coliform
the portion of the coliform bacteria group which is present in the intestinal tracts and feces of warm-blooded animals. A common pollutant in water.

filter
a device used to remove solids from a mixture or to separate materials. Materials are frequently separated from water using filters.

filtration
the mechanical process which removes particulate matter by separating water from solid material, usually by passing it through sand.

flocculation
large scale treatment process involving gentle stirring whereby small particles in flocs are collected into larger particles so their weight causes them to settle to the bottom of the treatment tank.

flow
the rate of water discharged from a source expressed in volume with respect to time.

fresh water
water containing less than 1,000 parts per million (ppm) of dissolved solids of any type. Compare saline water.

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G

gallon
A unit of volume. A U.S. gallon contains 231 cubic inches, 0.133 cubic feet, or 3.785 liters. One U.S. gallon of water weighs 8.3 lbs.

granular activated carbon (GAC)
pure carbon heated to promote "active" sites which can adsorb pollutants. Used in some home water treatment systems to remove certain organic chemicals and radon.

greywater
wastewater from clothes washing machines, showers, bathtubs, handwashing, lavatories and sinks that are not used for disposal of chemical or chemical-biological ingredients.

groundwater
water within the earth that supplies wells and springs; water in the zone of saturation where all openings in rocks and soil are filled, the upper surface of which forms the water table.

groundwater remediation
treatment systems or processes to remove hazards or contaminants from water within the earth

groundwater runoff
the portion of runoff which has passed into the ground, has become ground water, and has been discharged into a stream channel as spring or seepage water.

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H

hard water
water containing a high level of calcium, magnesium, and other minerals. Hard water reduces the cleansing power of soap and produces scale in hot water lines and appliances.

hormite
hormite clays are chain silicates having certain structural features in common with both tremolite and antigorite, although hormites have a silica layer on both sides of the octahedral layer, silica sheet inversions limit the width of the octahedral sheet, allowing it to grow in only one direction.

hydrocarbons
Chemical compounds that contain hydrogen and carbon. Most motor vehicles and engines are powered by hydrocarbon-based fuels such as gasoline and diesel.

hydrophilic
having a strong attraction to water. Hydrophilic molecules are soluble in water and travel with the groundwater.

hydrophobic
to repel water; water-repulsing adsorbents, often used to extract oil from water

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I

impermeable
material that does not permit fluids to pass through.

impervious
the quality or state of being impermeable; resisting penetration by water or plant roots. Impervious ground cover like concrete and asphalt affects quantity and quality of runoff.

indicator tests
tests for a specific contaminant, group of contaminants, or constituent which signals the presence of something else (ex., coliforms indicate the presence of pathogenic bacteria).

influent
The water entering the pump, the filter or other equipment of space. Water going into the pump is called in influent, while water leaving the pump is called the effluent.

interlamellar
Between lamellae or laminae; as, interlamellar spaces.

ionic bonding
bond in which one or more electrons from one atom are removed and attached to another atom, resulting in positive and negative ions which attract each other.

irrigation water
water which is applied to assist crops in areas or during times where rainfall is inadequate.

isotherm
line that connects points of equal temperature.

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J

jetty
a structure (as a pier or mole of wood or stone) extending into a sea, lake, or river to influence the current or tide or to protect a harbor.

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K

kame
a short ridge, hill, or mound of stratified drift deposited by glacial meltwater.

kame terrace
a terrace of stratified sand and and gravel deposited by streams between a glacier and an adjacent valley wall.

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L

laboratory water
purified water used in the laboratory as a basis for making up solutions or making dilutions. Water devoid of interfering substances.

lagoon
a shallow pond where sunlight, bacterial action, and oxygen work to purify wastewater. Lagoons are typically used for the storage of wastewaters, sludges, liquid wastes, or spent nuclear fuel.

lamella
a thin plate or scale of anything, as a thin scale growing from the petals of certain flowers; or one of the thin plates or scales of which certain shells are composed.

langmir isotherm
developed by Irving Langmuir in 1916 to describe the dependence of the surface coverage of an adsorbed gas on the pressure of the gas above the surface at a fixed temperature, providing insight into the pressure dependence of the extent of surface adsorption.

leachate
water containing contaminants which leaks from a disposal site such as a landfill or dump.

leaching
extraction or flushing out of dissolved or suspended materials from the soil, solid waste, or another medium by water or other liquids as they percolate down through the medium to groundwater.

lignite
A young coal used almost exclusively for electric power generation. It is brownish black in color and has a high moisture content, sometimes as high as 45 percent, and a high ash content. It tends to disintegrate when exposed to the weather. Also referred to as brown coal.

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M

median streamflow
the rate of discharge of a stream for which there are equal numbers of greater and lesser flow occurrences during a specified period.

meteoric water
new water derived from the atmosphere.

micrograms per liter - Ug/L
micrograms per liter of water. One thousands micrograms per liter is equivalent to 1 milligram per liter. This measure is equivalent to parts per billion (ppb)

migration
the movement of oil, gas, contaminants, water, or other liquids through porous and permeable rock.

milligrams per liter - mg/L
milligrams per liter of water. This measure is equivalent to parts per million (ppm).

montmorillonite
an aluminum silicate (smectite) with a 2:1 layer structure composed of two silica tetrahedral sheets and a shared aluminum and magnesium octahedral sheet. Montmorillonite has a permanent negative charge that attracts interlayer cations that exist in various degrees of hydration thus causing expansion and collapse of the structure (i.e., shrink-swell).

municipal treatment plant
centrally located systems designed to treat water collected from a community which may be composed of domestic wastewater, sewage, industrial wastes or both.

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N

natural resource
any form of matter or energy obtained from the environment that meets human needs.

NPDES permit
permit issued under the National Pollutant Discharge Elimination System for companies discharging pollutants directly into the waters of the United States.

NAPL
(non-aqueous phase liquid) - Layer or film of fluid immiscible with water.

NTU
nephlometric turbidity units.

nutrient
as a pollutant, any element or compound, such as phosphorous or nitrogen, that fuels abnormally high organic growth in aquatic ecosystems. Also see eutrophic.

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O

oil removal
to remove oil from another element by means of adsorption or other chemical processes.

oil spill cleanup
An accidental or intentional discharge of oil which reaches bodies of water. Can be controlled by chemical dispersion, combustion, mechanical containment, and/or adsorption. Spills from tanks and pipelines can also occur away from water bodies, contaminating the soil, getting into sewer systems and threatening underground water sources.

oleophilic
having a strong attraction to oils, (of a) substance that mixes readily with oils.

organophilic
a chemical or molecular orientation favoring the attraction of hydrocarbons or materials which are miscible in hydrocarbons. Organophilic materials are characterized by weak dipole moments. They are basically immiscible in water.

organoclay
organically modified clay consisting of bentonite, composed mainly of the clay mineral montmorillonite, which is modified with quaternary amines.

organic chemicals
chemicals containing carbon.

ozonation
a water treatment process that destroys bacteria and other microorganisms through an infusion of ozone, a gas produced by subjecting oxygen molecules to high electrical voltages.

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P

PAH
Polynuclear Aromatic Hydrocarbon. Multi-ring compounds found in fuels, oils, and creosote. These are also common combustion products.

pathogen
microorganisms which can cause disease.

PCP
Pentachlorophenol. A toxic white crystalline compound, used in solution as a fungicide and wood preservative. Very toxic by inhalation. Toxic by ingestion. Inhalation or ingestion may be fatal. Risk of irreversible effects. Severe eye irritant. Inhalation may cause poisoning of the circulatory system with possible heart failure. Readily absorbed through the skin.

peak flow
in a wastewater treatment plant, the highest flow expected to be encoutered under any operational conditions, including periods of high rainfall and prolonged periods of wet weather.

permeability
the ability of a water bearing material to transmit water. It is measured by the quantity of water passing through a unit cross section, in a unit time, under 100 percent hydraulic gradient.

permeable reactive barriers
an emplacement of reactive materials in the subsurface designed to intercept a contaminant plume, provide a preferential flow path through the reactive media, and transform the contaminant(s) into environmentally acceptable forms to attain remediation concentration goals at the discharge of the barrier.

pH
numeric value that describes the intensity of the acid or basic (alkaline) conditions of a solution. The pH scale is from 0 to 14, with the neutral point at 7.0. Values lower than 7 indicate the presence of acids and greater than 7.0 the presence of alkalis (bases). Technically speaking, pH is the logarithm of the reciprocal (negative log) of the hydrogen ion concentration (hydrogen ion activity) in moles per liter.

phosphorous
a plant nutrient that can cause an overabundance of bacteria and algae when high amounts are present, leading to a depletion of oxygen and fish kills. High levels of phosphorous in water are usually caused by agricultural runoff or improperly operating wastewater treatment plants. Also see nitrogen.

phyllosilicates
group of silicate minerals that have each set of tetrahedrons surrounded by three oxygen atoms, forming a sheet like structure.

phytoremediation
the use of plants to remediate contamination by the uptake (transpiration) of contaminated water by plants. Plants can be used to contain, remove, or degrade contaminants.

pollution
undesireable change in the physical, chemical, or biological characteristics of the air, water, or land that can harmfully affect the health, survival, or activities of human or other living organisms.

pond
a body of water usually smaller than a lake and larger than a pool either naturally or artificially confined.

porous
something which allows water to pass through it. Compare nonporous.

potable
suitable, safe, or prepared for drinking. Compare non-potable.

ppb - parts per billion
number of parts of a chemical found in one billion parts of a solid, liquid, or gaseous mixture. Equivalent to micrograms per liter (Ug/L).

ppm - parts per million
number of parts of a chemical found in one million parts of a solid, liquid, or gaseous mixture. Equivalent to milligrams per liter (mg/L).

primary treatment
mechanical treatment in which large solids are screened out and suspended solids in the sewage settle out as sludge. Compare secondary treatment, tertiary treatment.

produced water
water associated with oil and gas reservoirs that is produced along with the oil and gas.

pump
a device which moves, compresses, or alters the pressure of a fluid, such as water or air, being conveyed through a natural or artificial channel.

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Q

QAC
quaternary ammonium compounds - the number of newer quaternaries is extensive and future technologies and applications are being constantly developed on this class of compounds.

quaternary
consisting of or especially arranged in sets of four

quarry water
the moisture content of freshly quarried stone, esp. if porous.

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R

reclamation water
domestic wastewater that is under the direct control of a treatment plant owner/operator which has been treated to a quality suitable for a beneficial use.

remediation
cleanup or other methods used to remove or contain a toxic spill or hazardous materials from a contaminated area.

runoff
surface water entering rivers, freshwater lakes, or reservoirs.

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S

saline water
water containing more than 1,000 parts per million (ppm) of dissolved solids of any type. Compare fresh water.

salinity
amount of dissolved salts in a given volume of water.

saturation
the condition of a liquid when it has taken into solution the maximum possible quantity of a given substance at a given temperature and pressure.

saponite
hydrous silicate of magnesia and alumina. It occurs in soft, soapy, amorphous masses, filling veins in serpentine and cavities in trap rock

secondary treatment
second step in most waste treatment systems, in which bacteria break down the organic parts of sewage wastes; usually accomplished by bringing the sewage and bacteria together in trickling filters or in the activated sludge process. Compare primary treatment, tertiary treatment. Compare primary treatment, tertiary treatment.

sediment
soil particles, sand, and minerals washed from the land into aquatic systems as a result of natural and human activities.

sediment cap
use of soil particles, sand, and minerals to place a clean layer of sediment to act as an effective means of containment of contaminants.

sedimentation
a large scale water treatment process where heavy solids settle out to the bottom of the treatment tank after flocculation.

seep
a spot where water contained in the ground oozes slowly to the surface and often forms a pool; a small spring.

separate sewer
a sewer system that carries only sanitary sewage, not stormwater runoff. When a sewer is constructed this way, wastewater treatment plants can be sized to treat sanitary wastes only and all of the water entering the plant receives complete treatment at all times. Comparecombined sewer.

septic tank
underground receptacle for wastewater from a home. The bacteria in the sewage decopose the organic wastes, and the sludge settles to the bottom of the tank. The effluent flows out of the tank into the ground through drains.

settleable solids
in sewage, suspended solids that will settle when the sewage is brought to a quiet state for a reasonable length of time, usually two hours.

silicate
rock or mineral whose structure is dominated by bonds of silicon and oxygen atoms (ie. olivine)

sludge
solid matter that settles to the bottom of sedimentation tanks in a sewage treatment plant and must be disposed of by digestion or other methods or recycled to the land.

smectite
A group of clay minerals that includes montmorillonite. This type of mineral tends to swell when exposed to water. Bentonite includes minerals of the smectite group.

stormwater runoff
precipitation that does not infiltrate into the ground or evaporate due to impervious land surfaces but instead flows onto adjacent land or water areas and is routed into drain/sewer systems.

subbituminous
also called Black Lignite, dark brown to black coal intermediate in rank between lignite and bituminous coal. Subbituminous coals often have a silky lustre and sometimes are macroscopically indistinguishable from the bituminous variety.

substrate
a term meaning, generally, a surface to which something adheres, the base material to be printed on, or the surface to which a pressure sensitive decal is adhered. In particular, any surface on which screen printing is applied.

surface water
water that flows in streams and rivers and in natural lakes, in wetlands, and in reservoirs constructed by humans.

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T

TCLP
Toxic Characteristic Leaching Procedure (TCLP) is an EPA SW-846 analytical method (Method 1311) that simulates sanitary landfill contaminant leaching in waste samples. Based upon concentrations of the TCLP constituents and guidelines set forth in 40 CFR 261.4, the solid waste samples can be deemed hazardous or non-hazardous.

technology-based treatment requirements
NPDES permit requirements based on the application of pollution treatment or control technologies including BTP (best practicable technology), BCT (best conventional technology), BAT (best available technology economically achievable), and NSPS (new source performance standards).

tertiary treatment
removal from wastewater of traces or organic chemicals and dissolved solids that remain after primary treatment and secondary treatment.

TDS - total dissolved solids
the sum or all inorganic and organic particulate material. TDS is an indicator test used for wastewater analysis and is also a measure of the mineral content of bottled water and groundwater. There is a relationship between TDS and conductivity. In general, for the San Antonio River basin, TDS/.6 approximates conductivity. Or, conductivity * .6 approximates TDS. People monitoring water quality can measure electrical conductivity quickly in the field and estimate TDS without doing any lab tests at all. See specific conductance.

Toxicity Reduction Evaluation (TRE)
a study conducted to determine the source(s) of toxicity in a discharge effluent so that these sources can be controlled sufficiently to allow a discharger to comply with their permit limits.

toxicity test
the means to determine the toxicity of a chemical or an effluent using living organisms. A toxicity test measures the degree of response of an exposed test organism to a specified chemical or effluent.

treatment
Any method, technique, or process, including neutralization, designed to change the physical or chemical character or composition of any hazardous waste so as to neutralize such waste or so as to render such waste nonhazardous, safer for transport, amenable for recovery, amenable for storage, or reduced in volume. Such terms includes any activity or processing designed to change the physical form or chemical composition of hazardous waste so as to render it nonhazardous.

turbidity
thick or opaque with matter in suspension. Rivers and lakes may become turbid after a rainfall.

turf reinforcement mat
Turf Reinforcement Mats (TRMs) combine vegetative growth and synthetic materials to form a high-strength mat that helps to prevent soil erosion in drainage areas and on steep slopes. TRMs are classified as a "soft engineering practice" which may replace concrete and rip rap in certain erosion control situations.

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U

upflow
an upward flow.

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V

van der Waals forces
The physical forces of attraction and repulsion existing between molecules and which are responsible for the cohesion of molecular crystals and liquids. The forces stem partly from dipole-dipole, or dipole-induced-dipole interactions; however, even nonpolar molecules and atoms exert a certain attraction on one another. Van der Waals forces act only over relatively short distances, and are proportional to the inverse of the seventh power of the intermolecular distances.

vested water right
the right granted by a state water agency to use either surface or ground water.

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W

wastewater
water containing waste including greywater, blackwater or water contaminated by waste contact, including process-generated and contaminated rainfall runoff.

wastewater treatment system
a system designed with the express purpose of removing waste or contaminants from water

water
the liquid that descends from the clouds as rain; forms streams, lakes, and seas, and is a major constituent of all living matter. It is an odorless, tasteless, colorless, very slightly compressible liquid.

water pollution
degradation of a body of water by a substance or condition to such a degree that the water fails to meet specified standards or cannot be used for a specific purpose.

water quality standards
laws or regulations, promulgated under Section 303 of the Clean Water Act, that consist of the designated use or uses of a waterbody or a segment of a waterbody and the water quality criteria that are necessary to protect the use or uses of that particular waterbody. Water quality standards also contain an antidegradation statement. Every State is required to develop water quality criteria standards applicable to the various waterbodies within the State and revise them every 3 yeaars.

whole-effluent toxicity
the aggregate toxic effect of an effluent measured directly by a toxicity test.

WQA
Water Quality Association is a non-profit organization representing the clean and pure drinking water industry for homes, farms, businesses and commercial/industrial use.

wyoming
location of high quality bentonite, called "wyoming bentonite"

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X

xeriscape
creative landscaping for water and energy efficiency and lower maintenance. The seven xeriscape principles are: good planning and design; practical lawn areas; efficient irrigation; soil improvement; use of mulches; low water demand plants; good maintenance.

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Y

yield
the quantity of water expressed either as a continuous rate of flow (cubic feet per second, etc.) or as a volume per unit of time. It can be collected for a given use, or uses, from surface or groundwater sources on a watershed.

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Z

zeolites
zeolite is a class of hydrated aluminosilicates found in certain volcanic rocks. Once upon a time, geologists thought these minerals were interesting because they consist of large cage-like structures with open channelways.

zone of saturation
the space below the water table in which all the interstices (pore spaces) are filled with water. Water in the zone of saturation is called groundwater.