|
Antidegradation Policy
[Why
are WQS Important?] [WQS
Review and Revision] [Role
of the Public] [Designated
Uses] [Water
Quality Criteria] [Antidegradation]
[General Policies]
[Indian Tribe Participation]
[WQS Program History]
Antidegradation Policy: Water quality standards
include an antidegradation policy and implementation method.
The water quality standards regulation requires States and Tribes
to establish a three-tiered antidegradation program.
Tier 1 maintains and protects existing uses and water
quality conditions necessary to support such uses. An existing
use can be established by demonstrating that fishing, swimming,
or other uses have actually occurred since November 28, 1975,
or that the water quality is suitable to allow such uses to occur.
Where an existing use is established, it must be protected even
if it is not listed in the water quality standards as a designated
use. Tier 1 requirements are applicable to all surface waters.
Tier 2 maintains and protects "high quality" waters --
water bodies where existing conditions are better than necessary
to support CWA § 101(a)(2) "fishable/swimmable" uses. Water
quality can be lowered in such waters. However, State and
Tribal Tier 2 programs identify procedures that must be followed
and questions that must be answered before a reduction in water
quality can be allowed. In no case may water quality be
lowered to a level which would interfere with existing or designated
uses.
Tier 3 maintains and protects water quality in outstanding
national resource waters (ONRWs). Except for certain temporary
changes, water quality cannot be lowered in such waters.
ONRWs generally include the highest quality waters of the United
States. However, the ONRW classification also offers special
protection for waters of exceptional ecological significance,
i.e., those which are important, unique, or sensitive ecologically.
Decisions regarding which water bodies qualify to be ONRWs are
made by States and authorized Indian Tribes.
Antidegradation implementation procedures identify the steps
and questions that must be addressed when regulated activities
are proposed that may affect water quality. The specific
steps to be followed depend upon which tier or tiers of antidegradation
apply.
|
