General Glossary

The transparency of stream water (in units of centimeters) as
measured in a Citizen Stream Monitoring Program transparency
tube. The transparency tube is a clear, 60 cm-long tube with
colored disk on the bottom for measuring depth at which disk is
visible. The clarity of stream water is an indicator of how much
sediment, algae, and other materials are suspended in the water.

The number of vehicles that could be receiving gasoline
simultaneously at a gasoline service station.

A closed system of pipes, hoses, and fittings, connecting a
gasoline-unloading tank and a gasoline-receiving tank at a
gasoline service station so that the vapors displaced from the
receiving tank are transferred to the unloading tank.

A specific degree of hotness or coldness as indicated on or
referred to a standard scale.

A designation that includes Great Lakes marine coastal waters
and estuaries designated by the Clean Water Act section 303c for
use for swimming, bathing, surfing or similar water contact
activities. This excludes inland waters, and waters upstream of
the mouth of a river or stream that has an impaired natural
connection with an open sea.

The unit used to describe turbidity. Nephelometric refers to the
way the instrument, a nephelometer, measures how much light is
scattered by suspended particles in the water. The greater the
scattering, the higher the turbidity. Therefore, low NTU values
indicate high water clarity, while high NTU values indicate low
water clarity.

A temperature-adjusted measurement of conductivity. Typically
measured in micromhos per centimeter (µmhos/cm).
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Conductivity varies depending on water temperature. Specific
conductance takes into account the water sample temperature to
yield a conductivity value as if the sample were at 25 degrees
Celsius.

Nitrate (NO3) plus nitrite (NO2) as nitrogen. In lakes, most
nitrate/nitrogen is in NO3 form. It is measured in milligrams
per liter (mg/L). Elevated levels of nitrates/nitrogen are
often caused by over application of fertilizers that leach into
waterbodies.

Total Nitrogen is the sum of nitrate (NO3), nitrite (NO2),
organic nitrogen and ammonia (all expressed as N). Note that
for laboratory analysis purposes, Total Kjeldahl Nitrogen (TKN)
is a test performed that is made up of both organic nitrogen
and ammonia.

Ground water under sufficient pressure to rise above the top of
the aquifer containing it.