GLOSSARY
                        Glossary of Terms Used in
                                 Studies and Folder

  Ajitidegradatioii policy — policy required by EPA's water quality standards regulation that
  States and authorized Indian tribes must adopt to conserve, maintain, and protect water quality thar
  is better than that necessary to protect designated uses,
                           — evaluation of the biological condition of a watertoody using
  biological surveys and other direct measurements of resident biota, in surface waters.

  Biological community — all the groups of organisms living together in Hie. saute area, usually
  interacting or depending on each other for existence.

  BMogkal criteria — narrative or numeric expressions (hat describe the desired biological
  condition of aquatic communities inhabiting particular lypes. of watef bodies.

  Biological integrity — the condition of the aquatic community inhabiting unimpaired
  watcrbodics of a specific habitat as measured by community structurv and function,

  Biological survey -- collecting, processing, and analyzing a representative portion of the
  resident aquatic community to determine its structural and/or functional characteristics.

1  Designated  use — the use defined in wacer quality standards as the goal for each watecbody or
  waterbody segment whether or not that use is being met.
  Impact — Lliange in Llie chemical, physical (including habitat), or biological quality or condition
  of a waterbody caused by natural occurrences ^e,g.? flood) or by man (e.g., pollution),
Macitiin vertebrate —
large enough to be seen
                                        backbones that live in or on ihe sediment. They are
                              using a microscope,
  Narrative biolugical criteria — general sialcmcnli thai describe the expected aquatic com-
  munity for a given designated aquatic life- use,

  Narrative criteria — criteria expressed in concise statements, generally in a "free from" for-
  mat, General statements of attainable or attained conditions of ecological integrity and water qual-
  ity far a given use designation.

  Nonpoint source pollution — pollution sources that arc diffuse and do not have a single
  point of origin Examples include runoff from agriculture, fonestryh and construction sites.

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Numeric biological criteria — quantitative indices that describe the expected aquatic
niry for a given designated aquatic life use.
Nutrients — thnse substances (e.g., nitrogen and phosphorus) that affect, the growth rate of
plants.
Point SOurCC pollution — pollution resulting from discharges into waters from any discernible,
curifinfid and discrete conveyance., such as a pipe, ditch^ or sewer.

Reference site — specific? place on. a waterbody chat 15 unimpaired or minimally impaired and
is representative of the expected Biological condition of other localities on the same waterbody or
nearby w'aterbodies,

KJparian zone — urea beside and along a watercourse mat often is vegetated and that is a buffer
zone between the nearby lands and watercourse.

Sedimentation — the deposition of fine materials (e.g., sand, silt, clay) onto the bottom of
streams and lakes.
Stressurs — chemical., physical., and biological factors thai adversely affect aquatic
and stream health.
Water quality criteria (narrative and numeric) — narrative water quality criteria are
concise .statements., generally in a '"free from"' format, of attainable or attained conditions of water
quality for a given use designation. Numeric water quality criteria are numericAl concentrations or
1 smits. for specific chemicals in water which, if not exceeded, will protect aquatic lite and human
health. All water quality criteria arc elements of walcr fjufjliiy sumJards adopted by stales and
authorized Indian tribes under Section 303(c) of die Clean Water Art.

Watershed — a drainage area or basin into which idl land and water areas drain or flow toward a
central collector, such as a river, stream or lake.

Water Quality Standards — the cornerstone of Indian tribal and stait water quality  manage-
ment programs. The water quality standards program consists of three components  (de&igjuired
usesr water quality criteria and the antidegradation policy) that  form (be legal basis far controls on
die amount of pollutants, a specific watcroody can contain. Water quality  standards describe the
quality of water that will support a specific use.

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