A State or Tribe's designated uses also must consider the water quality standards of downstream waters.

Key Point.The State or Tribe's water quality standards must provide for the attainment and maintenance of the downstream water quality standards.

Waterbody uses that must not be allowed by the State/Tribal uses (40 CFR 131.10):

It must not

Provide for waste transport or assimilation as a designated use.

It must not

Remove an existing use (unless adding a use with a more stringent criterion).

It must not

Allow a use that is less than those specified by Section 101(a) (unless justified by the attainability analysis).

Designated Uses: Allowable Uses That May Be Specified

Waterbody uses that can be allowed by the State/Tribal uses (40 CFR 131.10):

Use A

Protection of uses higher than those currently being achieved. Also, you may establish more stringent water quality criteria than required by the regulation.

Use B

Adoption of seasonal uses (e.g., in northern climates, in-water (or primary) recreational uses are possible only a few months out of the year).

Use C

Adoption of subcategories of a use:

• Appropriate criteria may be set to reflect the "varying needs" of such uses.
• When adopting subcategories with less stringent criteria, a use attainability analysis is required.

Use D

Removal of uses (if justified by the attainability analysis).

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