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Table 2-2. Components of Water Quality Standards

Water Quality
Standards Component  Definition
Designated Uses   Those uses specified in water quality     standards for each water body or segment     whether or not they are being attained     (40 CFR §131.3).  Typical uses include     public water supplies, propagation of     fish and wildlife, recreation,     agriculture, industry, or navigation.
Water Quality Criteria  Elements of State water quality standards,     expressed as constituent concentrations,     levels, or narrative statements,     representing a quality of water that     supports a particular use.  When criteria     are met, water quality will generally     protect the designated use (40 CFR §131.3)
Antidegradation   Antidegradation is a policy required in     State water quality standards to protect     their waters from degradation.  At a     minimum, States must maintain and protect     the quality of waters to support existing     uses.  Antidegradation was originally     based on the spirit, intent, and goals of     the Clean Water Act, especially the clause     "...restore and maintain the chemical,     physical, and biological integrity of the     Nation's waters".
Adapted from:
Water Quality Standards Handbook: Second Edition. 1994. EPA 823-B-94-005a. Office of Water.

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