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Laboratory
water: Purified
water used in the laboratory as a basis for making up solutions or making dilutions.
Water devoid of interfering substances.
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Lag time: The time from
the center of a unit storm to the peak discharge or center of volume of the
corresponding unit hydrograph.
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Lagoon: (1) A shallow
pond where sunlight, bacterial action, and oxygen work to purify wastewater.
(2) A shallow body of water, often separated from the sea by coral reefs or
sandbars.
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Lake: Any inland body
of standing water, usually fresh water, larger than a pool or pond; a body of
water filling a depression in the earth's surface.
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Laminar
flow: A flow
in which rapid fluctuations are absent.
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Land Application: Discharge of
wastewater onto the ground for treatment or reuse.
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Landscape
impoundment:
Body of reclaimed water which is used for aesthetic enjoyment or which otherwise
serves a function not intended to include contact recreation.
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Landscape
irrigation: Water
conservation through landscaping that uses plants that need little water, thereby
saving labor and fertilizer as well as water.
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Langelier
Index (LI): An
index reflecting the equilibrium pH of a water with respect to calcium and alkalinity;
used in stabilizing water to control both corrosion and scale deposition.
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Large water
system: A water
system that services more than 50,000 customers.
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Leachate: Water containing
contaminants which leaks from a disposal site such as a landfill or dump.
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Leaching: The removal of
soluble organic and inorganic substances from the topsoil downward by the action
of percolating water.
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Leak detection: Systematic method
of using listening equipment to survey the distribution system, identify leak
sounds, and pinpoint the exact locations of hidden underground leaks.
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Leakage: A species of
ions in the feed of an ion exchanger present in the effluent.
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Lentic system: A nonflowing
or standing body of fresh water, such as a lake or pond. Compare lotic system.
-
Levee: A natural or
man-made earthen obstruction along the edge of a stream, lake, or river. Usually
used to restrain the flow of water out of a river bank.
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Light absorption: The amount of
light a certain amount of water can absorb over time.
-
Lime: Common water
treatment chemical. Lime can be deposed on walls of showers and bathrooms, after
lime has reacted with calcium to form limestone.
-
Limestone: Rock that consists
mainly of calcium carbonate and is chiefly formed by accumulation of organic
remains.
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Limiting
factor: Factor
such as temperature, light, water, or a chemical that limits the existence,
growth, abundance, or distribution of an organism.
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Limnology: Scientific study
of physical, chemical, and biological conditions in lakes, ponds, and streams.
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Liquid: A state of matter,
neither gas nor solid, that flows and takes the shape of its container.
-
Liter: The basic unit
of measurement for volume in the metric system; equal to 61.025 cubic inches
or 1.0567 liquid quarts.
-
Liter per minute (Lpm):
unit of flow.
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Littoral zone: Area on or near the shore of a body of water.
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Livestock
water use: Water
for livestock watering, feed lots, dairy operations, fish farming, and other
on-farm needs. Livestock as used here includes cattle, sheep, goats, hogs, and
poultry. Also included are animal specialties. See also rural water use and
animal specialties water use.
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Lotic system: A flowing body
of fresh water, such as a river or stream. Compare lentic system.
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Low-flow
plumbing: Plumbing
equipment that uses less water than was considered standard prior to January
1, 1994.
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Low-flow
showerhead: A
showerhead that requires 2.5 gallons of water per minute or less, as compared
to the 4.5 gallons of water required by most older standard showerheads.
-
Low-flush
toilet: A toilet
that requires 1.6 gallons of water per flush or less, as compared to the 3.5-5
gallons of water required to flush most older standard toilets.
