water used in the laboratory as a basis for making up solutions or making dilutions.
Water devoid of interfering substances.
Lag time: The time from
the center of a unit storm to the peak discharge or center of volume of the
corresponding unit hydrograph.
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
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.
flow: A flow
in which rapid fluctuations are absent.
Land Application: Discharge of
wastewater onto the ground for treatment or reuse.
Body of reclaimed water which is used for aesthetic enjoyment or which otherwise
serves a function not intended to include contact recreation.
conservation through landscaping that uses plants that need little water, thereby
saving labor and fertilizer as well as water.
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.
system: A water
system that services more than 50,000 customers.
Leachate: Water containing
contaminants which leaks from a disposal site such as a landfill or dump.
Leaching: The removal of
soluble organic and inorganic substances from the topsoil downward by the action
of percolating water.
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.
Leakage: A species of
ions in the feed of an ion exchanger present in the effluent.
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.
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
such as temperature, light, water, or a chemical that limits the existence,
growth, abundance, or distribution of an organism.
Limnology: Scientific study
of physical, chemical, and biological conditions in lakes, ponds, and streams.
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.
Littoral zone: Area on or near the shore of a body of water.
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.
Lotic system: A flowing body
of fresh water, such as a river or stream. Compare lentic system.
equipment that uses less water than was considered standard prior to January
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.
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.