Simply put, antidegradation means that no pollutant discharges or activities will be permitted if these may cause surface waters already meeting water quality standards to drop below those standards. But the various colorations within that general meaning provide states with many opportunities to permit activities that do in fact degrade surface waters.
As EPA notes in the strategy, standards and regulations implemented under the CWA have been overwhelmingly oriented toward cleanup of highly polluted water. But the explicit goal of the CWA is to “restore and maintain the chemical, physical, and biological integrity of the Nation’s waters” (emphasis added). Through regulations, EPA directed states to establish antidegradation programs to place waters into one of three tiers and assign protections accordingly.
Tier 1—Water quality must be maintained to protect existing uses of waters. The most common designated uses are fishable and swimmable. No new or increased pollutant discharges that would lower water quality necessary to support those uses may be permitted. States make such designations or change existing designations, but protection must occur even if there is no official designation of that use. EPA reviews and approves/disapproves the designations.
Tier 2—Refers to high-quality waters, those waters where existing conditions are better than necessary to support designated uses. Water quality may be lowered for Tier 2 waters, for example, for compelling economic reasons, but may not be lowered to a level that would interfere with existing or designated uses.
Tier 3—Refers to outstanding national resource waters (ONRW). Except for temporary changes, water quality may not be lowered in these waters.
Tier 2.5—Not a federal tier, but adopted by some states to allow limited development in conjunction with high-quality waters that do not have the Tier 3 designation.
Among the problems associated with antidegradation are the variations in policy and implementation. Each state must have an antidegradation policy and a plan to implement that policy. Implementation would, for example, govern how national pollutant discharge elimination (NPDES) permits would be granted for waters subject to antidegradation designations. Some have charged that states have developed policies but have failed to rigorously implement them, leading to discharges that have lowered water quality.
States have also been involved in controversies when permitting discharges lower the quality of Tier 2 waters. Criteria for justifying economic necessity are ill-defined and vary from state to state. In its strategy, EPA notes particular concern about mining activities that degrade surface water. It would be hard to argue against the necessity for such actions in economically stressed regions of the country where mining is prevalent. However, EPA is concerned that states are enabling discharges simply by not designating Tier 3 waters. Some environmentalists are arguing that the public should be allowed to petition to designate waters as Tier 3.
EPA’s clean water strategy notes several directions the Agency intends to take to address the problems being faced by high- quality waters under the antidegradation policy.
Specifically, EPA states that it will develop a common set of comprehensive metrics to create a national list of healthy watersheds; use the full suite of CWA tools to protect high-quality streams from destruction and degradation caused by mining activities; propose changes to the federal water quality regulations to clarify and strengthen antidegradation regulations to protect high-quality waters; and ensure states are—and, where EPA has permitting authority, EPA is—applying antidegradation effectively in NPDES permitting programs.