Water Science Glossary of Terms
hperlman[at]usgs.gov
http://ga.water.usgs.gov/edu/dictionary.html
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Here's
a list of water-related terms that might help you
understand our site better. It is compiled from a
number of sources and should not be considered an
"official" U.S. Geological Survey water
glossary. A detailed water glossary is kept by the
Water
Quality Association, and an extremely
detailed water dictionary is offered by the
Nevada Division of Water Planning).
A
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acequia - acequias
were important forms of irrigation in the development
of agriculture in the American Southwest. The
proliferation of cotton, pecans and green chile
as major agricultual staples owe their progress
to the acequia system. acid
- a substance that has a pH
of less than 7, which is neutral. Specifically,
an acid has more free hydrogen ions (H+)
than hydroxyl ions (OH-).
acre-foot
(acre-ft) - the volume of water required
to cover 1 acre of land (43,560 square feet)
to a depth of 1 foot. Equal to 325,851 gallons
or 1,233 cubic meters.
alkaline - sometimes
water or soils contain an amount of alkali (strongly
basic) substances sufficient to raise the pH
value above 7.0 and be harmful to the growth
of crops.
alkalinity - the
capacity of water for neutralizing an acid solution.
alluvium - deposits
of clay, silt, sand, gravel, or other particulate
material that has been deposited by a stream
or other body of running water in a streambed,
on a flood plain, on a delta, or at the base
of a mountain.
appropriation
doctrine - the system for allocating
water to private individuals used in most Western
states. The doctrine of Prior Appropriation
was in common use throughout the arid west as
early settlers and miners began to develop the
land. The prior appropriation doctrine is based
on the concept of "First in Time, First
in Right." The first person to take a quantity
of water and put it to Beneficial Use has a
higher priority of right than a subsequent user.
Under drought conditions, higher priority users
are satisfied before junior users receive water.
Appropriative rights can be lost through nonuse;
they can also be sold or transferred apart from
the land. Contrasts with Riparian Water Rights.
aquaculture - farming
of plants and animals that live in water, such
as fish, shellfish, and algae.
aqueduct - a
pipe, conduit, or channel designed to transport
water from a remote source, usually by gravity.
aquifer - a
geologic formation(s) that is water bearing.
A geological formation or structure that stores
and/or transmits water, such as to wells and
springs. Use of the term is usually restricted
to those water-bearing formations capable of
yielding water in sufficient quantity to constitute
a usable supply for people's uses.
aquifer
(confined) - soil or rock below the
land surface that is saturated with water. There
are layers of impermeable material both above
and below it and it is under pressure so that
when the aquifer is penetrated by a well, the
water will rise above the top of the aquifer.
aquifer
(unconfined) - an aquifer whose upper
water surface (water table) is at atmospheric
pressure, and thus is able to rise and fall.
artesian
water - ground water that is under
pressure when tapped by a well and is able to
rise above the level at which it is first encountered.
It may or may not flow out at ground level.
The pressure in such an aquifer commonly is
called artesian pressure, and the formation
containing artesian water is an artesian aquifer
or confined aquifer. See flowing
well
artificial
recharge - an process where water is
put back into ground-water storage from surface-water
supplies such as irrigation, or induced infiltration
from streams or wells.
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B
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base
flow - streamflow coming from ground-water
seepage into a stream. base
- a substance that has a pH
of more than 7, which is neutral. A base has
less free hydrogen ions (H+) than
hydroxyl ions (OH-).
bedrock
- the solid rock beneath the soil and superficial
rock. A general term for solid rock that lies
beneath soil, loose sediments, or other unconsolidated
material.
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C
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capillary
action - the means by which liquid moves
through the porous spaces in a solid, such as
soil, plant roots, and the capillary blood vessels
in our bodies due to the forces of adhesion, cohesion,
and surface tension. Capillary action is essential
in carrying substances and nutrients from one
place to another in plants and animals.
commercial
water use - water used for motels,
hotels, restaurants, office buildings, other
commercial facilities, and institutions. Water
for commercial uses comes both from public-supplied
sources, such as a county water department,
and self-supplied sources, such as local wells.
condensation
- the process of water vapor in the air turning
into liquid water. Water drops on the outside
of a cold glass of water are condensed water.
Condensation is the opposite process of evaporation.
consumptive
use - that part of water withdrawn
that is evaporated, transpired by plants, incorporated
into products or crops, consumed by humans or
livestock, or otherwise removed from the immediate
water environment. Also referred to as water
consumed.
conveyance
loss - water that is lost in transit
from a pipe, canal, or ditch by leakage or evaporation.
Generally, the water is not available for further
use; however, leakage from an irrigation ditch,
for example, may percolate to a ground-water
source and be available for further use.
cubic
feet per second (cfs) - a rate of the
flow, in streams and rivers, for example. It
is equal to a volume of water one foot high
and one foot wide flowing a distance of one
foot in one second. One "cfs" is equal
to 7.48 gallons of water flowing each second.
As an example, if your car's gas tank is 2 feet
by 1 foot by 1 foot (2 cubic feet), then gas
flowing at a rate of 1 cubic foot/second would
fill the tank in two seconds.
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D
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desalinization
- the removal of salts from saline water to provide
freshwater. This method is becoming a more popular
way of providing freshwater to populations.
discharge
- the volume of water that passes a given location
within a given period of time. Usually expressed
in cubic feet per second.
domestic
water use - water used for household
purposes, such as drinking, food preparation,
bathing, washing clothes, dishes, and dogs,
flushing toilets, and watering lawns and gardens.
About 85% of domestic water is delivered to
homes by a public-supply facility, such as a
county water department. About 15% of the Nation's
population supply their own water, mainly from
wells.
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. Large
drainage basins, like the area that drains into
the Mississippi River contain thousands of smaller
drainage basins. Also called a "watershed."
drip
irrigation - a common irrigation method
where pipes or tubes filled with water slowly
drip onto crops. Drip irrigation is a low-pressure
method of irrigation and less water is lost
to evaporation than high-pressure spray
irrigation.
drawdown
- a lowering of the ground-water surface caused
by pumping.
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E
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effluent
- water that flows from a sewage treatment plant
after it has been treated. erosion
- the process in which a material is worn away
by a stream of liquid (water) or air, often
due to the presence of abrasive particles in
the stream.
estuary
- a place where fresh and salt water mix, such
as a bay, salt marsh, or where a river enters
an ocean.
evaporation
- the process of liquid water becoming water
vapor, including vaporization from water surfaces,
land surfaces, and snow fields, but not from
leaf surfaces. See transpiration
evapotranspiration
- the sum of evaporation and transpiration.
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F
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flood
- An overflow of water onto lands that are used
or usable by man and not normally covered by water.
Floods have two essential characteristics: The
inundation of land is temporary; and the land
is adjacent to and inundated by overflow from
a river, stream, lake, or ocean. flood,
100-year - A 100-year flood does not
refer to a flood that occurs once every 100
years, but to a flood level with a 1 percent
chance of being equaled or exceeded in any given
year.
flood
plain - a strip of relatively flat
and normally dry land alongside a stream, river,
or lake that is covered by water during a flood.
flood
stage - The elevation at which overflow
of the natural banks of a stream or body of
water begins in the reach or area in which the
elevation is measured.
flowing
well/spring - a well or spring that
taps ground water under pressure so that water
rises without pumping. If the water rises above
the surface, it is known as a flowing well.
freshwater,
freshwater - water that contains less
than 1,000 milligrams per liter (mg/L) of dissolved
solids; generally, more than 500 mg/L of dissolved
solids is undesirable for drinking and many
industrial uses.
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G
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gage
height - the height of the water surface
above the gage datum (zero point). Gage height
is often used interchangeably with the more general
term, stage, although gage height is more appropriate
when used with a gage reading. gaging
station - a site on a stream, lake,
reservoir or other body of water where observations
and hydrologic data are obtained. The U.S. Geological
Survey measures stream discharge at gaging stations.
geyser
- a geothermal feature of the Earth where there
is an opening in the surface that contains superheated
water that periodically erupts in a shower of
water and steam.
giardiasis
- a disease that results from an infection by
the protozoan parasite Giardia Intestinalis,
caused by drinking water that is either not
filtered or not chlorinated. The disorder is
more prevalent in children than in adults and
is characterized by abdominal discomfort, nausea,
and alternating constipation and diarrhea.
glacier
- a huge mass of ice, formed on land by the
compaction and recrystallization of snow, that
moves very slowly downslope or outward due to
its own weight.
greywater
- wastewater from clothes washing machines,
showers, bathtubs, hand washing, lavatories
and sinks.
ground
water - (1) water that flows or seeps
downward and saturates soil or rock, supplying
springs and wells. The upper surface of the
saturate zone is called the water table. (2)
Water stored underground in rock crevices and
in the pores of geologic materials that make
up the Earth's crust.
ground
water, confined - ground water under
pressure significantly greater than atmospheric,
with its upper limit the bottom of a bed with
hydraulic conductivity distinctly lower than
that of the material in which the confined water
occurs.
ground-water
recharge - inflow of water to a ground-water
reservoir from the surface. Infiltration of
precipitation and its movement to the water
table is one form of natural recharge. Also,
the volume of water added by this process.
ground
water, unconfined - water in an aquifer
that has a water table that is exposed to the
atmosphere.
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H
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hardness
- a water-quality indication of the concentration
of alkaline salts in water, mainly calcium and
magnesium. If the water you use is "hard"
then more soap, detergent or shampoo is necessary
to raise a lather. headwater(s)
- (1) the source and upper reaches of a stream;
also the upper reaches of a reservoir. (2) the
water upstream from a structure or point on
a stream. (3) the small streams that come together
to form a river. Also may be thought of as any
and all parts of a river basin except the mainstream
river and main tributaries.
hydroelectric
power water use - the use of water
in the generation of electricity at plants where
the turbine generators are driven by falling
water.
hydrologic
cycle - the cyclic transfer of water
vapor from the Earth's surface via evapotranspiration
into the atmosphere, from the atmosphere via
precipitation back to earth, and through runoff
into streams, rivers, and lakes, and ultimately
into the oceans.
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I
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impermeable
layer - a layer of solid material, such
as rock or clay, which does not allow water to
pass through. industrial
water use - water used for industrial
purposes in such industries as steel, chemical,
paper, and petroleum refining. Nationally, water
for industrial uses comes mainly (80%) from
self-supplied sources, such as a local wells
or withdrawal points in a river, but some water
comes from public-supplied sources, such as
the county/city water department.
infiltration
- flow of water from the land surface into the
subsurface.
injection
well - refers to a well constructed
for the purpose of injecting treated wastewater
directly into the ground. Wastewater is generally
forced (pumped) into the well for dispersal
or storage into a designated aquifer. Injection
wells are generally drilled into aquifers that
don't deliver drinking water, unused aquifers,
or below freshwater levels.
irrigation
- the controlled application of water for agricultural
purposes through manmade systems to supply water
requirements not satisfied by rainfall. Here's
a quick
look at some types of irrigation systems.
irrigation
water use - water application on lands
to assist in the growing of crops and pastures
or to maintain vegetative growth in recreational
lands, such as parks and golf courses.
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K
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kilogram
- one thousand grams. kilowatthour
(KWH) - a power demand of 1,000 watts
for one hour. Power company utility rates are
typically expressed in cents per kilowatt-hour.
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L
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leaching
- the process by which soluble materials in the
soil, such as salts, nutrients, pesticide chemicals
or contaminants, are washed into a lower layer
of soil or are dissolved and carried away by water.
lentic
waters - ponds or lakes (standing water).
levee
- a natural or manmade earthen barrier along
the edge of a stream, lake, or river. Land alongside
rivers can be protected from flooding by levees.
livestock
water use - water used for livestock
watering, feed lots, dairy operations, fish
farming, and other on-farm needs.
lotic
waters - flowing waters, as in streams
and rivers.
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M
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maximum
contaminant level (MCL) - the designation
given by the U.S. Environmental Protection Agency
(EPA) to water-quality standards promulgated under
the Safe Drinking Water Act. The MCL is the greatest
amount of a contaminant that can be present in
drinking water without causing a risk to human
health. milligram
(mg) - One-thousandth of a gram.
milligrams
per liter (mg/l) - a unit of the concentration
of a constituent in water or wastewater. It
represents 0.001 gram of a constituent in 1
liter of water. It is approximately equal to
one part per million (PPM).
million
gallons per day (Mgd) - a rate of flow
of water equal to 133,680.56 cubic feet per
day, or 1.5472 cubic feet per second, or 3.0689
acre-feet per day. A flow of one million gallons
per day for one year equals 1,120 acre-feet
(365 million gallons).
mining
water use - water use during quarrying
rocks and extracting minerals from the land.
municipal
water system - a water system that
has at least five service connections or which
regularly serves 25 individuals for 60 days;
also called a public water system
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N
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nephelometric
turbidity unit (NTU) - unit of measure
for the turbidity of water. Essentially, a measure
of the cloudiness of water as measured by a nephelometer.
Turbidity is based on the amount of light that
is reflected off particles in the water.
non-point
source (NPS) pollution - pollution
discharged over a wide land area, not from one
specific location. These are forms of diffuse
pollution caused by sediment, nutrients, organic
and toxic substances originating from land-use
activities, which are carried to lakes and streams
by surface runoff. Non-point source pollution
is contamination that occurs when rainwater,
snowmelt, or irrigation washes off plowed fields,
city streets, or suburban backyards. As this
runoff moves across the land surface, it picks
up soil particles and pollutants, such as nutrients
and pesticides.
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O
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organic
matter - plant and animal residues, or
substances made by living organisms. All are based
upon carbon compounds. osmosis
- the movement of water molecules through a
thin membrane. The osmosis process occurs in
our bodies and is also one method of desalinizing
saline water.
outfall
- the place where a sewer, drain, or stream
discharges; the outlet or structure through
which reclaimed water or treated effluent is
finally discharged to a receiving water body.
oxygen
demand - the need for molecular oxygen
to meet the needs of biological and chemical
processes in water. Even though very little
oxygen will dissolve in water, it is extremely
important in biological and chemical processes.
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P
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pH
- a measure of the relative acidity or alkalinity
of water. Water with a pH of 7 is neutral; lower
pH levels indicate increasing acidity, while pH
levels higher than 7 indicate increasingly basic
solutions.
View a diagram
about pH.
particle
size - the diameter, in millimeters,
of suspended sediment or bed material. Particle-size
classifications are:
[1] Clay—0.00024-0.004 millimeters (mm);
[2] Silt—0.004-0.062 mm;
[3] Sand—0.062-2.0 mm; and
[4] Gravel—2.0-64.0 mm.
parts
per billion - the number of "parts"
by weight of a substance per billion parts of
water. Used to measure extremely small concentrations.
parts
per million - the number of "parts"
by weight of a substance per million parts of
water. This unit is commonly used to represent
pollutant concentrations.
pathogen
- a disease-producing agent; usually applied
to a living organism. Generally, any viruses,
bacteria, or fungi that cause disease.
peak
flow - the maximum instantaneous discharge
of a stream or river at a given location. It
usually occurs at or near the time of maximum
stage.
per
capita use - the average amount of
water used per person during a standard time
period, generally per day.
percolation
- (1) The movement of water through the openings
in rock or soil. (2) the entrance of a portion
of the streamflow into the channel materials
to contribute to ground water replenishment.
permeability
- the ability of a material to allow the passage
of a liquid, such as water through rocks. Permeable
materials, such as gravel and sand, allow water
to move quickly through them, whereas unpermeable
material, such as clay, don't allow water to
flow freely.
point-source
pollution - water pollution coming
from a single point, such as a sewage-outflow
pipe.
polychlorinated
biphenyls (PCBs) - a group of synthetic,
toxic industrial chemical compounds once used
in making paint and electrical transformers,
which are chemically inert and not biodegradable.
PCBs were frequently found in industrial wastes,
and subsequently found their way into surface
and ground waters. As a result of their persistence,
they tend to accumulate in the environment.
In terms of streams and rivers, PCBs are drawn
to sediment, to which they attach and can remain
virtually indefinitely. Although virtually banned
in 1979 with the passage of the Toxic Substances
Control Act, they continue to appear in the
flesh of fish and other animals.
porosity
- a measure of the water-bearing capacity of
subsurface rock. With respect to water movement,
it is not just the total magnitude of porosity
that is important, but the size of the voids
and the extent to which they are interconnected,
as the pores in a formation may be open, or
interconnected, or closed and isolated. For
example, clay may have a very high porosity
with respect to potential water content, but
it constitutes a poor medium as an aquifer because
the pores are usually so small.
potable
water - water of a quality suitable
for drinking.
precipitation
- rain, snow, hail, sleet, dew, and frost.
primary
wastewater treatment - the first stage
of the wastewater-treatment process where mechanical
methods, such as filters and scrapers, are used
to remove pollutants. Solid material in sewage
also settles out in this process.
prior
appropriation doctrine - the system
for allocating water to private individuals
used in most Western states. The doctrine of
Prior Appropriation was in common use throughout
the arid West as early settlers and miners began
to develop the land. The prior appropriation
doctrine is based on the concept of "First
in Time, First in Right." The first person
to take a quantity of water and put it to beneficial
use has a higher priority of right than a subsequent
user. The rights can be lost through nonuse;
they can also be sold or transferred apart from
the land. Contrasts with riparian water rights.
public
supply - water withdrawn by public
governments and agencies, such as a county water
department, and by private companies that is
then delivered to users. Public suppliers provide
water for domestic, commercial, thermoelectric
power, industrial, and public water users. Most
people's household water is delivered by a public
water supplier. The systems have at least 15
service connections (such as households, businesses,
or schools) or regularly serve at least 25 individuals
daily for at least 60 days out of the year.
public
water use - water supplied from a public-water
supply and used for such purposes as firefighting,
street washing, and municipal parks and swimming
pools.
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R
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rating
curve - A drawn curve showing the relation
between gage height and discharge of a stream
at a given gaging station. recharge
- water added to an aquifer. For instance, rainfall
that seeps into the ground.
reclaimed
wastewater - treated wastewater that
can be used for beneficial purposes, such as
irrigating certain plants.
recycled
water - water that is used more than
one time before it passes back into the natural
hydrologic system.
reservoir
- a pond, lake, or basin, either natural or
artificial, for the storage, regulation, and
control of water.
return
flow - (1) That part of a diverted
flow that is not consumptively used and returned
to its original source or another body of water.
(2) (Irrigation) Drainage water from irrigated
farmlands that re-enters the water system to
be used further downstream.
returnflow
(irrigation) - irrigation water that
is applied to an area and which is not consumed
in evaporation or transpiration and returns
to a surface stream or aquifer.
reverse
osmosis - (1) (Desalination) The process
of removing salts from water using a membrane.
With reverse osmosis, the product water passes
through a fine membrane that the salts are unable
to pass through, while the salt waste (brine)
is removed and disposed. This process differs
from electrodialysis, where the salts are extracted
from the feedwater by using a membrane with
an electrical current to separate the ions.
The positive ions go through one membrane, while
the negative ions flow through a different membrane,
leaving the end product of freshwater. (2) (Water
Quality) An advanced method of water or wastewater
treatment that relies on a semi-permeable membrane
to separate waters from pollutants. An external
force is used to reverse the normal osmotic
process resulting in the solvent moving from
a solution of higher concentration to one of
lower concentration.
riparian
water rights - the rights of an owner
whose land abuts water. They differ from state
to state and often depend on whether the water
is a river, lake, or ocean. The doctrine of
riparian rights is an old one, having its origins
in English common law. Specifically, persons
who own land adjacent to a stream have the right
to make reasonable use of the stream. Riparian
users of a stream share the streamflow among
themselves, and the concept of priority of use
(Prior Appropriation Doctrine) is not applicable.
Riparian rights cannot be sold or transferred
for use on nonriparian land.
river
- A natural stream of water of considerable
volume, larger than a brook or creek.
runoff
- (1) That part of the precipitation, snow melt,
or irrigation water that appears in uncontrolled
surface streams, rivers, drains or sewers. Runoff
may be classified according to speed of appearance
after rainfall or melting snow as direct runoff
or base runoff, and according to source as surface
runoff, storm interflow, or ground-water runoff.
(2) The total discharge described in (1), above,
during a specified period of time. (3) Also
defined as the depth to which a drainage area
would be covered if all of the runoff for a
given period of time were uniformly distributed
over it. |
S
|
saline
water - water that contains significant
amounts of dissolved solids.
Here are our parameters for saline water:
Fresh water - Less than 1,000 parts per
million (ppm)
Slightly saline water - From 1,000 ppm to
3,000 ppm
Moderatly saline water - From 3,000 ppm
to 10,000 ppm
Highly saline water - From 10,000 ppm to
35,000 ppm |
secondary
wastewater treatment - treatment (following
primary wastewater treatment) involving the biological
process of reducing suspended, colloidal, and
dissolved organic matter in effluent from primary
treatment systems and which generally removes
80 to 95 percent of the Biochemical Oxygen Demand
(BOD) and suspended matter. Secondary wastewater
treatment may be accomplished by biological or
chemical-physical methods. Activated sludge and
trickling filters are two of the most common means
of secondary treatment. It is accomplished by
bringing together waste, bacteria, and oxygen
in trickling filters or in the activated sludge
process. This treatment removes floating and settleable
solids and about 90 percent of the oxygen-demanding
substances and suspended solids. Disinfection
is the final stage of secondary treatment.
sediment
- usually applied to material in suspension
in water or recently deposited from suspension.
In the plural the word is applied to all kinds
of deposits from the waters of streams, lakes,
or seas.
sedimentary
rock - rock formed of sediment, and
specifically: (1) sandstone and shale, formed
of fragments of other rock transported from
their sources and deposited in water; and (2)
rocks formed by or from secretions of organisms,
such as most limestone. Many sedimentary rocks
show distinct layering, which is the result
of different types of sediment being deposited
in succession.
sedimentation
tanks - wastewater tanks in which floating
wastes are skimmed off and settled solids are
removed for disposal.
self-supplied
water - water withdrawn from a surface-
or ground-water source by a user rather than
being obtained from a public supply. An example
would be homeowners getting their water from
their own well.
seepage
- (1) The slow movement of water through small
cracks, pores, Interstices, etc., of a material
into or out of a body of surface or subsurface
water. (2) The loss of water by infiltration
into the soil from a canal, ditches, laterals,
watercourse, reservoir, storage facilities,
or other body of water, or from a field.
septic
tank - a tank used to detain domestic
wastes to allow the settling of solids prior
to distribution to a leach field for soil absorption.
Septic tanks are used when a sewer line is not
available to carry them to a treatment plant.
A settling tank in which settled sludge is in
immediate contact with sewage flowing through
the tank, and wherein solids are decomposed
by anaerobic bacterial action.
settling
pond (water quality)--an open lagoon
into which wastewater contaminated with solid
pollutants is placed and allowed to stand. The
solid pollutants suspended in the water sink
to the bottom of the lagoon and the liquid is
allowed to overflow out of the enclosure.
sewage
treatment plant - a facility designed
to receive the wastewater from domestic sources
and to remove materials that damage water quality
and threaten public health and safety when discharged
into receiving streams or bodies of water. The
substances removed are classified into four
basic areas:
[1] greases and fats;
[2] solids from human waste and other sources;
[3] dissolved pollutants from human waste and
decomposition products; and
[4] dangerous microorganisms.
Most facilities employ a combination of mechanical
removal steps and bacterial decomposition to
achieve the desired results. Chlorine is often
added to discharges from the plants to reduce
the danger of spreading disease by the release
of pathogenic bacteria.
sewer
- a system of underground pipes that collect
and deliver wastewater to treatment facilities
or streams.
sinkhole
- a depression in the Earth's surface caused
by dissolving of underlying limestone, salt,
or gypsum. Drainage is provided through underground
channels that may be enlarged by the collapse
of a cavern roof.
solute
- a substance that is dissolved in another substance,
thus forming a solution.
solution
- a mixture of a solvent and a solute. In some
solutions, such as sugar water, the substances
mix so thoroughly that the solute cannot be
seen. But in other solutions, such as water
mixed with dye, the solution is visibly changed.
solvent
- a substance that dissolves other substances,
thus forming a solution. Water dissolves more
substances than any other, and is known as the
"universal solvent".
specific
conductance - a measure of the ability
of water to conduct an electrical current as
measured using a 1-cm cell and expressed in
units of electrical conductance, i.e., Siemens
per centimeter at 25 degrees Celsius. Specific
conductance can be used for approximating the
total dissolved solids content of water by testing
its capacity to carry an electrical current.
In water quality, specific conductance is used
in ground water monitoring as an indication
of the presence of ions of chemical substances
that may have been released by a leaking landfill
or other waste storage or disposal facility.
A higher specific conductance in water drawn
from downgradient wells when compared to upgradient
wells indicates possible contamination from
the facility.
spray
irrigation - an common irrigation method
where water is shot from high-pressure sprayers
onto crops. Because water is shot high into
the air onto crops, some water is lost to evaporation.
storm
sewer - a sewer that carries only surface
runoff, street wash, and snow melt from the
land. In a separate sewer system, storm sewers
are completely separate from those that carry
domestic and commercial wastewater (sanitary
sewers).
stream
- a general term for a body of flowing water;
natural water course containing water at least
part of the year. In hydrology, it is generally
applied to the water flowing in a natural channel
as distinct from a canal.
streamflow
- the water discharge that occurs in a natural
channel. A more general term than runoff, streamflow
may be applied to discharge whether or not it
is affected by diversion or regulation.
subsidence
- a dropping of the land surface as a result
of ground water being pumped. Cracks and fissures
can appear in the land. Subsidence is virtually
an irreversible process.
surface
tension - the attraction of molecules
to each other on a liquid's surface. Thus, a
barrier is created between the air and the liquid.
surface
water - water that is on the Earth's
surface, such as in a stream, river, lake, or
reservoir.
suspended
sediment - very fine soil particles
that remain in suspension in water for a considerable
period of time without contact with the bottom.
Such material remains in suspension due to the
upward components of turbulence and currents
and/or by suspension.
suspended-sediment
concentration - the ratio of the mass
of dry sediment in a water-sediment mixture
to the mass of the water-sediment mixture. Typically
expressed in milligrams of dry sediment per
liter of water-sediment mixture.
suspended-sediment
discharge - the quantity of suspended
sediment passing a point in a stream over a
specified period of time. When expressed in
tons per day, it is computed by multiplying
water discharge (in cubic feet per second) by
the suspended-sediment concentration (in milligrams
per liter) and by the factor 0.0027.
suspended
solids - solids that are not in true
solution and that can be removed by filtration.
Such suspended solids usually contribute directly
to turbidity. Defined in waste management, these
are small particles of solid pollutants that
resist separation by conventional methods.
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T
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tertiary
wastewater treatment - selected biological,
physical, and chemical separation processes to
remove organic and inorganic substances that resist
conventional treatment practices; the additional
treatment of effluent beyond that of primary and
secondary treatment methods to obtain a very high
quality of effluent. The complete wastewater treatment
process typically involves a three-phase process:
(1) First, in the primary wastewater treatment
process, which incorporates physical aspects,
untreated water is passed through a series of
screens to remove solid wastes; (2) Second, in
the secondary wastewater treatment process, typically
involving biological and chemical processes, screened
wastewater is then passed a series of holding
and aeration tanks and ponds; and (3) Third, the
tertiary wastewater treatment process consists
of flocculation basins, clarifiers, filters, and
chlorine basins or ozone or ultraviolet radiation
processes. thermal
pollution - a reduction in water quality
caused by increasing its temperature, often
due to disposal of waste heat from industrial
or power generation processes. Thermally polluted
water can harm the environment because plants
and animals can have a hard time adapting to
it.
thermoelectric
power water use - water used in the
process of the generation of thermoelectric
power. Power plants that burn coal and oil are
examples of thermoelectric-power facilities.
transmissibility
(ground water) - the capacity of a
rock to transmit water under pressure. The coefficient
of transmissibility is the rate of flow of water,
at the prevailing water temperature, in gallons
per day, through a vertical strip of the aquifer
one foot wide, extending the full saturated
height of the aquifer under a hydraulic gradient
of 100-percent. A hydraulic gradient of 100-percent
means a one foot drop in head in one foot of
flow distance.
transpiration
- process by which water that is absorbed by
plants, usually through the roots, is evaporated
into the atmosphere from the plant surface,
such as leaf pores. See evapotranspiration.
Tributary
- a smaller river or stream that flows into
a larger river or stream. Usually, a number
of smaller tributaries merge to form a river.
turbidity
- the amount of solid particles that are suspended
in water and that cause light rays shining through
the water to scatter. Thus, turbidity makes
the water cloudy or even opaque in extreme cases.
Turbidity is measured in nephelometric turbidity
units (NTU).
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U
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unsaturated
zone - the zone immediately below the
land surface where the pores contain both water
and air, but are not totally saturated with water.
These zones differ from an aquifer,
where the pores are saturated with water.
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W
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wastewater
- water that has been used in homes, industries,
and businesses that is not for reuse unless it
is treated. wastewater-treatment
return flow - water returned to the
environment by wastewater-treatment facilities.
water
cycle - the circuit of water
movement from the oceans to the atmosphere and
to the Earth and return to the atmosphere through
various stages or processes such as precipitation,
interception, runoff, infiltration, percolation,
storage, evaporation, and transportation.
water
quality - a term used to describe the
chemical, physical, and biological characteristics
of water, usually in respect to its suitability
for a particular purpose.
water
table - the top of the water surface
in the saturated part of an aquifer.
water
use - water that is used for a specific
purpose, such as for domestic use, irrigation,
or industrial processing. Water use pertains
to human's interaction with and influence on
the hydrologic cycle, and includes elements,
such as water withdrawal from surface- and ground-water
sources, water delivery to homes and businesses,
consumptive use of water, water released from
wastewater-treatment plants, water returned
to the environment, and instream uses, such
as using water to produce hydroelectric power.
watershed
- the land area that drains water to a particular
stream, river, or lake. 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. Large watersheds, like
the Mississippi River basin contain thousands
of smaller watersheds.
watthour
(Wh) - an electrical energy unit of
measure equal to one watt of power supplied
to, or taken from, an electrical circuit steadily
for one hour.
well
(water) - an artificial excavation
put down by any method for the purposes of withdrawing
water from the underground aquifers. A bored,
drilled, or driven shaft, or a dug hole whose
depth is greater than the largest surface dimension
and whose purpose is to reach underground water
supplies or oil, or to store or bury fluids
below ground.
withdrawal
- water removed from a ground- or surface-water
source for use.
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X
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xeriscaping
- a method of landscaping that uses plants that
are well adapted to the local area and are drought-resistant.
Xeriscaping is becoming more popular as a way
of saving water at home.
More on xeriscaping:
Texas Natural Resource Center
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Y
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yield
- mass per unit time per unit area
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