Key Concepts

Parameters:  High Quality Waters (Tier 2)

Tier 2 of the State or Tribe's antidegradation program protects "high quality" waters—that is, water bodies where existing water quality conditions are better than necessary to protect CWA 101(a) uses.

High quality waters must be addressed by the State or Tribe's antidegradation program because of the importance of such waters as a resource with economic, public health, and ecological value.

Key Point. Trade-offs must be carefully considered before a high quality water resource is allowed to be diminished in any way through degradation of water quality. The State or Tribe's antidegradation program must identify a procedure to be followed and questions to be addressed when confronting such issues.

Learn More. Two ways to identify high quality waters. Also, information about antidegradation review for high quality waters. Proceed to the Learn More Topic. »